feat(derivatives): leverage, OI/volume, perpetual premium, funding APR, OI momentum (B16) (#214)

## B16 Derivatives — five new indicators (488 → 493)

All consume a `DerivativesTick` and emit `f64`:

| Indicator | Reads | Formula |
|-----------|-------|---------|
| `EstimatedLeverageRatio` | open_interest, long_size, short_size | `OI / (long + short)` |
| `OiToVolumeRatio` | open_interest, taker_buy_volume, taker_sell_volume | `OI / (buy + sell)` |
| `PerpetualPremiumIndex` | mark_price, index_price | `(mark − index) / index` |
| `FundingImpliedApr` | funding_rate | `rate × intervals_per_year` |
| `OpenInterestMomentum` | open_interest | `100 · (OI_t − OI_{t−period}) / OI_{t−period}` |

### Wiring
- Core structs + full unit tests (incl. zero-denominator branches).
- Hand-written Python/Node/WASM tick bindings; two new tick helpers (`deriv_oi_long_short`, `deriv_oi_taker`).
- Fuzz drives in `indicator_update_derivatives.rs`; dedicated reference + streaming-vs-batch tests (Python + Node).
- README counter + `docs/README.md` + `FAMILIES` assert bumped to 493.

### Verify (local, all green)
- `cargo test -p wickra-core --lib`: 4028 · `--doc`: 443
- clippy workspace: clean
- node: 563 · pytest: 928

CHANGELOG.md

@@ -6,6 +6,11 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+- **Open-Interest Momentum** — rate-of-change of open interest over a rolling window (`OpenInterestMomentum`).
+- **Funding-Implied APR** — annualised funding rate (per-interval funding times intervals per year) (`FundingImpliedApr`).
+- **Perpetual Premium Index** — relative premium of the mark price over the index price (`PerpetualPremiumIndex`).
+- **OI-to-Volume Ratio** — open interest divided by taker volume (position turnover proxy) (`OiToVolumeRatio`).
+- **Estimated Leverage Ratio** — open interest divided by aggregate long+short position size (leverage proxy) (`EstimatedLeverageRatio`).
 
 ## [0.7.0] - 2026-06-08
 - **Hasbrouck Information Share** — variance-ratio proxy for each venue's share of price discovery (Hasbrouck information share) (`HasbrouckInformationShare`).

README.md

@@ -1,5 +1,5 @@
 <p align="center">
-  <a href="https://wickra.org"><img src="https://raw.githubusercontent.com/wickra-lib/.github/main/profile/wickra-banner.webp?v=488" alt="Wickra — streaming-first technical indicators" width="100%"></a>
+  <a href="https://wickra.org"><img src="https://raw.githubusercontent.com/wickra-lib/.github/main/profile/wickra-banner.webp?v=493" alt="Wickra — streaming-first technical indicators" width="100%"></a>
 </p>
 
 [![CI](https://github.com/wickra-lib/wickra/actions/workflows/ci.yml/badge.svg)](https://github.com/wickra-lib/wickra/actions/workflows/ci.yml)
@@ -48,7 +48,7 @@ Full documentation lives at **[docs.wickra.org](https://docs.wickra.org)**:
   [Node](https://docs.wickra.org/Quickstart-Node),
   [WASM](https://docs.wickra.org/Quickstart-WASM).
 - **Indicators** — a per-indicator deep dive (formula, parameters, warmup) for
-  every one of the 488 indicators; start at the
+  every one of the 493 indicators; start at the
   [indicators overview](https://docs.wickra.org/Indicators-Overview).
 - **Reference** — [warmup periods](https://docs.wickra.org/Warmup-Periods),
   [streaming vs batch](https://docs.wickra.org/Streaming-vs-Batch),
@@ -66,7 +66,7 @@ an afterthought — **live, tick-by-tick data** — without giving up the breadt
 a full batch library, and without making you reimplement your indicators four
 times to get there.
 
-- **The biggest streaming-native catalogue, period.** 488 indicators across 24
+- **The biggest streaming-native catalogue, period.** 493 indicators across 24
   families — candlesticks, harmonic & chart patterns, market profile, market
   breadth, Renko/Kagi/Point&Figure bars, Ehlers DSP cycles, risk/performance
   metrics — every single one updating in **O(1) per tick**. TA-Lib ships ~150 and
@@ -77,7 +77,7 @@ times to get there.
 - **Correct by construction, not by hope.** Every `update` validates its input,
   runs a real warmup, and returns an `Option` so a single bad tick can't silently
   poison state. `batch == streaming` is **bit-exact, fuzzed and 100 %-line-covered
-  for all 488 indicators**.
+  for all 493 indicators**.
 - **Orders of magnitude faster where it counts.** In streaming Wickra is **11–56×**
   faster than the only other incremental peer and **thousands of times** faster
   than recompute-on-every-tick libraries. On batch it wins several rows outright
@@ -95,7 +95,7 @@ Every other library forces one of those compromises. Wickra doesn't:
 
 | Library          | Install     | Streaming   | Languages                   | Indicators | Active |
 |------------------|-------------|-------------|-----------------------------|-----------:|--------|
-| **★&nbsp;Wickra**| **clean**   | **yes, O(1)** | **Python · Node · WASM · Rust** | **488** | **yes** |
+| **★&nbsp;Wickra**| **clean**   | **yes, O(1)** | **Python · Node · WASM · Rust** | **493** | **yes** |
 | kand             | clean       | yes         | Python · WASM · Rust        |       ~60  | yes    |
 | ta-rs            | clean       | yes         | Rust only                   |       ~30  | stale  |
 | yata             | clean       | partial     | Rust only                   |       ~35  | yes    |
@@ -128,7 +128,7 @@ Full tables (Rust + Python, streaming + batch) and how to reproduce them live in
 
 ## Indicators
 
-488 streaming-first indicators across twenty-four families. Every one passes the
+493 streaming-first indicators across twenty-four families. Every one passes the
 `batch == streaming` equivalence test, reference-value tests, and reset
 semantics tests. Each has a per-indicator deep dive (formula, parameters,
 warmup) at [docs.wickra.org](https://docs.wickra.org/Indicators-Overview).
@@ -154,7 +154,7 @@ warmup) at [docs.wickra.org](https://docs.wickra.org/Indicators-Overview).
 | Harmonic Patterns    | AB=CD, Gartley, Butterfly, Bat, Crab, Shark, Cypher, Three Drives |
 | Fibonacci            | Fibonacci Retracement, Fibonacci Extension, Fibonacci Projection, Auto-Fibonacci, Golden Pocket, Fibonacci Confluence, Fibonacci Fan, Fibonacci Arcs, Fibonacci Channel, Fibonacci Time Zones |
 | Microstructure       | Order-Book Imbalance (Top-1 / Top-N / Full), Microprice, Quoted Spread, Depth Slope, Signed Volume, Cumulative Volume Delta, Trade Imbalance, Effective Spread, Realized Spread, Kyle's Lambda, Footprint, Order Flow Imbalance, VPIN, Amihud Illiquidity, Roll Measure, Trade-Sign Autocorrelation, Hasbrouck Information Share |
-| Derivatives          | Funding Rate, Funding Rate Mean, Funding Rate Z-Score, Funding Basis, Open-Interest Delta, OI / Price Divergence, OI-Weighted Price, Long/Short Ratio, Taker Buy/Sell Ratio, Liquidation Features, Term-Structure Basis, Calendar Spread |
+| Derivatives          | Funding Rate, Funding Rate Mean, Funding Rate Z-Score, Funding Basis, Open-Interest Delta, OI / Price Divergence, OI-Weighted Price, Long/Short Ratio, Taker Buy/Sell Ratio, Liquidation Features, Term-Structure Basis, Calendar Spread, Estimated Leverage Ratio, OI-to-Volume Ratio, Perpetual Premium Index, Funding-Implied APR, Open-Interest Momentum |
 | Market Profile       | Value Area (POC / VAH / VAL), Volume Profile (histogram), TPO Profile, Initial Balance, Opening Range |
 | Market Breadth       | Advance/Decline Line, Advance/Decline Ratio, Advance/Decline Volume Line, McClellan Oscillator, McClellan Summation Index, TRIN / Arms Index, Breadth Thrust, New Highs - New Lows, High-Low Index, Percent Above Moving Average, Up/Down Volume Ratio, Bullish Percent Index, Cumulative Volume Index, Absolute Breadth Index, TICK Index |
 | Risk / Performance   | Sharpe Ratio, Sortino Ratio, Calmar Ratio, Omega Ratio, Max Drawdown, Average Drawdown, Drawdown Duration, Pain Index, Value at Risk, Conditional Value at Risk (CVaR), Profit Factor, Gain/Loss Ratio, Recovery Factor, Kelly Criterion, Treynor Ratio, Information Ratio, Alpha (Jensen) |
@@ -237,7 +237,7 @@ A Python live-trading example using the public `websockets` package lives at
 ```
 wickra/
 ├── crates/
-│   ├── wickra-core/         core engine + all 488 indicators
+│   ├── wickra-core/         core engine + all 493 indicators
 │   ├── wickra/              top-level facade crate (publishes on crates.io) + benches/
 │   ├── wickra-data/         CSV reader, tick aggregator, live exchange feeds
 │   └── wickra-bench/        internal cross-library benchmark harness (not published)

bindings/node/__tests__/indicators.test.js

@@ -1443,6 +1443,56 @@ test('derivatives reject bad input', () => {
   assert.throws(() => new wickra.FundingBasis().update(100, 0));
 });
 
+test('B16 derivatives reference values', () => {
+  // Estimated leverage: oi / (long + short) = 200 / 100 = 2.
+  assert.ok(Math.abs(new wickra.EstimatedLeverageRatio().update(200, 60, 40) - 2.0) < 1e-12);
+  // OI-to-volume: oi / (buy + sell) = 100 / 50 = 2.
+  assert.ok(Math.abs(new wickra.OiToVolumeRatio().update(100, 30, 20) - 2.0) < 1e-12);
+  // Perpetual premium: (mark - index) / index = 0.5 / 100 = 0.005.
+  assert.ok(Math.abs(new wickra.PerpetualPremiumIndex().update(100.5, 100.0) - 0.005) < 1e-12);
+  // Funding-implied APR: rate * intervals = 0.0001 * 1095 = 0.1095.
+  assert.ok(Math.abs(new wickra.FundingImpliedApr(1095).update(0.0001) - 0.1095) < 1e-12);
+  // Open-interest momentum (period 2): warmup then ROC% = 100*(120 - 100)/100 = 20.
+  const oim = new wickra.OpenInterestMomentum(2);
+  assert.equal(oim.update(100), null);
+  assert.equal(oim.update(110), null);
+  assert.ok(Math.abs(oim.update(120) - 20.0) < 1e-12);
+});
+
+test('B16 derivatives streaming matches batch', () => {
+  const n = 30;
+  const oi = Array.from({ length: n }, (_, i) => 1000 + 50 * Math.sin(i * 0.3));
+  const longSz = Array.from({ length: n }, (_, i) => 600 + 20 * Math.cos(i * 0.2));
+  const shortSz = Array.from({ length: n }, (_, i) => 400 + 15 * Math.sin(i * 0.4));
+  const buy = Array.from({ length: n }, (_, i) => 300 + 10 * Math.sin(i * 0.5));
+  const sell = Array.from({ length: n }, (_, i) => 250 + 12 * Math.cos(i * 0.35));
+  const index = Array.from({ length: n }, (_, i) => 100 + Math.sin(i * 0.2));
+  const mark = Array.from({ length: n }, (_, i) => index[i] + 0.05 * Math.cos(i * 0.3));
+  const rate = Array.from({ length: n }, (_, i) => 0.0001 * Math.sin(i * 0.3));
+  const cmp = (batch, s, i) =>
+    assert.ok((s === null && Number.isNaN(batch[i])) || Math.abs(s - batch[i]) < 1e-12, `mismatch at ${i}`);
+
+  let b = new wickra.EstimatedLeverageRatio().batch(oi, longSz, shortSz);
+  let st = new wickra.EstimatedLeverageRatio();
+  for (let i = 0; i < n; i++) cmp(b, st.update(oi[i], longSz[i], shortSz[i]), i);
+
+  b = new wickra.OiToVolumeRatio().batch(oi, buy, sell);
+  st = new wickra.OiToVolumeRatio();
+  for (let i = 0; i < n; i++) cmp(b, st.update(oi[i], buy[i], sell[i]), i);
+
+  b = new wickra.PerpetualPremiumIndex().batch(mark, index);
+  st = new wickra.PerpetualPremiumIndex();
+  for (let i = 0; i < n; i++) cmp(b, st.update(mark[i], index[i]), i);
+
+  b = new wickra.FundingImpliedApr(1095).batch(rate);
+  st = new wickra.FundingImpliedApr(1095);
+  for (let i = 0; i < n; i++) cmp(b, st.update(rate[i]), i);
+
+  b = new wickra.OpenInterestMomentum(10).batch(oi);
+  st = new wickra.OpenInterestMomentum(10);
+  for (let i = 0; i < n; i++) cmp(b, st.update(oi[i]), i);
+});
+
 test('market breadth: AdvanceDecline reference values', () => {
   // A breadth tick is the universe as parallel arrays; the sign of `change`
   // classifies each symbol as advancing / declining / unchanged.

bindings/node/index.d.ts

@@ -4544,6 +4544,51 @@ export declare class CalendarSpread {
   isReady(): boolean
   warmupPeriod(): number
 }
+export type EstimatedLeverageRatioNode = EstimatedLeverageRatio
+export declare class EstimatedLeverageRatio {
+  constructor()
+  update(openInterest: number, longSize: number, shortSize: number): number | null
+  batch(openInterest: Array<number>, longSize: Array<number>, shortSize: Array<number>): Array<number>
+  reset(): void
+  isReady(): boolean
+  warmupPeriod(): number
+}
+export type OiToVolumeRatioNode = OiToVolumeRatio
+export declare class OiToVolumeRatio {
+  constructor()
+  update(openInterest: number, takerBuyVolume: number, takerSellVolume: number): number | null
+  batch(openInterest: Array<number>, takerBuyVolume: Array<number>, takerSellVolume: Array<number>): Array<number>
+  reset(): void
+  isReady(): boolean
+  warmupPeriod(): number
+}
+export type PerpetualPremiumIndexNode = PerpetualPremiumIndex
+export declare class PerpetualPremiumIndex {
+  constructor()
+  update(markPrice: number, indexPrice: number): number | null
+  batch(markPrice: Array<number>, indexPrice: Array<number>): Array<number>
+  reset(): void
+  isReady(): boolean
+  warmupPeriod(): number
+}
+export type FundingImpliedAprNode = FundingImpliedApr
+export declare class FundingImpliedApr {
+  constructor(intervalsPerYear: number)
+  update(fundingRate: number): number | null
+  batch(fundingRate: Array<number>): Array<number>
+  reset(): void
+  isReady(): boolean
+  warmupPeriod(): number
+}
+export type OpenInterestMomentumNode = OpenInterestMomentum
+export declare class OpenInterestMomentum {
+  constructor(period: number)
+  update(openInterest: number): number | null
+  batch(openInterest: Array<number>): Array<number>
+  reset(): void
+  isReady(): boolean
+  warmupPeriod(): number
+}
 export type AdvanceDeclineNode = AdvanceDecline
 export declare class AdvanceDecline {
   constructor()

bindings/node/src/lib.rs

@@ -14450,6 +14450,50 @@ fn deriv_taker(taker_buy_volume: f64, taker_sell_volume: f64) -> napi::Result<wc
     .map_err(map_err)
 }
 
+fn deriv_oi_long_short(
+    open_interest: f64,
+    long_size: f64,
+    short_size: f64,
+) -> napi::Result<wc::DerivativesTick> {
+    wc::DerivativesTick::new(
+        0.0,
+        1.0,
+        1.0,
+        1.0,
+        open_interest,
+        long_size,
+        short_size,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0,
+    )
+    .map_err(map_err)
+}
+
+fn deriv_oi_taker(
+    open_interest: f64,
+    taker_buy_volume: f64,
+    taker_sell_volume: f64,
+) -> napi::Result<wc::DerivativesTick> {
+    wc::DerivativesTick::new(
+        0.0,
+        1.0,
+        1.0,
+        1.0,
+        open_interest,
+        0.0,
+        0.0,
+        taker_buy_volume,
+        taker_sell_volume,
+        0.0,
+        0.0,
+        0,
+    )
+    .map_err(map_err)
+}
+
 fn deriv_liquidation(
     long_liquidation: f64,
     short_liquidation: f64,
@@ -15165,6 +15209,288 @@ impl CalendarSpreadNode {
     }
 }
 
+// Estimated leverage ratio: open interest over aggregate long+short size.
+#[napi(js_name = "EstimatedLeverageRatio")]
+pub struct EstimatedLeverageRatioNode {
+    inner: wc::EstimatedLeverageRatio,
+}
+
+impl Default for EstimatedLeverageRatioNode {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+#[napi]
+impl EstimatedLeverageRatioNode {
+    #[napi(constructor)]
+    pub fn new() -> Self {
+        Self {
+            inner: wc::EstimatedLeverageRatio::new(),
+        }
+    }
+    #[napi]
+    pub fn update(
+        &mut self,
+        open_interest: f64,
+        long_size: f64,
+        short_size: f64,
+    ) -> napi::Result<Option<f64>> {
+        Ok(self
+            .inner
+            .update(deriv_oi_long_short(open_interest, long_size, short_size)?))
+    }
+    #[napi]
+    pub fn batch(
+        &mut self,
+        open_interest: Vec<f64>,
+        long_size: Vec<f64>,
+        short_size: Vec<f64>,
+    ) -> napi::Result<Vec<f64>> {
+        if open_interest.len() != long_size.len() || long_size.len() != short_size.len() {
+            return Err(NapiError::from_reason(
+                "open_interest, long_size, short_size must be equal length".to_string(),
+            ));
+        }
+        let mut out = Vec::with_capacity(open_interest.len());
+        for i in 0..open_interest.len() {
+            out.push(
+                self.inner
+                    .update(deriv_oi_long_short(
+                        open_interest[i],
+                        long_size[i],
+                        short_size[i],
+                    )?)
+                    .unwrap_or(f64::NAN),
+            );
+        }
+        Ok(out)
+    }
+    #[napi]
+    pub fn reset(&mut self) {
+        self.inner.reset();
+    }
+    #[napi(js_name = "isReady")]
+    pub fn is_ready(&self) -> bool {
+        self.inner.is_ready()
+    }
+    #[napi(js_name = "warmupPeriod")]
+    pub fn warmup_period(&self) -> u32 {
+        self.inner.warmup_period() as u32
+    }
+}
+
+// OI-to-volume ratio: open interest over taker buy+sell volume.
+#[napi(js_name = "OiToVolumeRatio")]
+pub struct OiToVolumeRatioNode {
+    inner: wc::OiToVolumeRatio,
+}
+
+impl Default for OiToVolumeRatioNode {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+#[napi]
+impl OiToVolumeRatioNode {
+    #[napi(constructor)]
+    pub fn new() -> Self {
+        Self {
+            inner: wc::OiToVolumeRatio::new(),
+        }
+    }
+    #[napi]
+    pub fn update(
+        &mut self,
+        open_interest: f64,
+        taker_buy_volume: f64,
+        taker_sell_volume: f64,
+    ) -> napi::Result<Option<f64>> {
+        Ok(self.inner.update(deriv_oi_taker(
+            open_interest,
+            taker_buy_volume,
+            taker_sell_volume,
+        )?))
+    }
+    #[napi]
+    pub fn batch(
+        &mut self,
+        open_interest: Vec<f64>,
+        taker_buy_volume: Vec<f64>,
+        taker_sell_volume: Vec<f64>,
+    ) -> napi::Result<Vec<f64>> {
+        if open_interest.len() != taker_buy_volume.len()
+            || taker_buy_volume.len() != taker_sell_volume.len()
+        {
+            return Err(NapiError::from_reason(
+                "open_interest, taker_buy_volume, taker_sell_volume must be equal length"
+                    .to_string(),
+            ));
+        }
+        let mut out = Vec::with_capacity(open_interest.len());
+        for i in 0..open_interest.len() {
+            out.push(
+                self.inner
+                    .update(deriv_oi_taker(
+                        open_interest[i],
+                        taker_buy_volume[i],
+                        taker_sell_volume[i],
+                    )?)
+                    .unwrap_or(f64::NAN),
+            );
+        }
+        Ok(out)
+    }
+    #[napi]
+    pub fn reset(&mut self) {
+        self.inner.reset();
+    }
+    #[napi(js_name = "isReady")]
+    pub fn is_ready(&self) -> bool {
+        self.inner.is_ready()
+    }
+    #[napi(js_name = "warmupPeriod")]
+    pub fn warmup_period(&self) -> u32 {
+        self.inner.warmup_period() as u32
+    }
+}
+
+// Perpetual premium index: relative premium of mark over index price.
+#[napi(js_name = "PerpetualPremiumIndex")]
+pub struct PerpetualPremiumIndexNode {
+    inner: wc::PerpetualPremiumIndex,
+}
+
+impl Default for PerpetualPremiumIndexNode {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+#[napi]
+impl PerpetualPremiumIndexNode {
+    #[napi(constructor)]
+    pub fn new() -> Self {
+        Self {
+            inner: wc::PerpetualPremiumIndex::new(),
+        }
+    }
+    #[napi]
+    pub fn update(&mut self, mark_price: f64, index_price: f64) -> napi::Result<Option<f64>> {
+        Ok(self.inner.update(deriv_basis(mark_price, index_price)?))
+    }
+    #[napi]
+    pub fn batch(&mut self, mark_price: Vec<f64>, index_price: Vec<f64>) -> napi::Result<Vec<f64>> {
+        if mark_price.len() != index_price.len() {
+            return Err(NapiError::from_reason(
+                "mark_price and index_price must be equal length".to_string(),
+            ));
+        }
+        let mut out = Vec::with_capacity(mark_price.len());
+        for i in 0..mark_price.len() {
+            out.push(
+                self.inner
+                    .update(deriv_basis(mark_price[i], index_price[i])?)
+                    .unwrap_or(f64::NAN),
+            );
+        }
+        Ok(out)
+    }
+    #[napi]
+    pub fn reset(&mut self) {
+        self.inner.reset();
+    }
+    #[napi(js_name = "isReady")]
+    pub fn is_ready(&self) -> bool {
+        self.inner.is_ready()
+    }
+    #[napi(js_name = "warmupPeriod")]
+    pub fn warmup_period(&self) -> u32 {
+        self.inner.warmup_period() as u32
+    }
+}
+
+// Funding-implied APR: per-interval funding annualised.
+#[napi(js_name = "FundingImpliedApr")]
+pub struct FundingImpliedAprNode {
+    inner: wc::FundingImpliedApr,
+}
+
+#[napi]
+impl FundingImpliedAprNode {
+    #[napi(constructor)]
+    pub fn new(intervals_per_year: f64) -> napi::Result<Self> {
+        Ok(Self {
+            inner: wc::FundingImpliedApr::new(intervals_per_year).map_err(map_err)?,
+        })
+    }
+    #[napi]
+    pub fn update(&mut self, funding_rate: f64) -> napi::Result<Option<f64>> {
+        Ok(self.inner.update(deriv_funding(funding_rate)?))
+    }
+    #[napi]
+    pub fn batch(&mut self, funding_rate: Vec<f64>) -> napi::Result<Vec<f64>> {
+        let mut out = Vec::with_capacity(funding_rate.len());
+        for r in funding_rate {
+            out.push(self.inner.update(deriv_funding(r)?).unwrap_or(f64::NAN));
+        }
+        Ok(out)
+    }
+    #[napi]
+    pub fn reset(&mut self) {
+        self.inner.reset();
+    }
+    #[napi(js_name = "isReady")]
+    pub fn is_ready(&self) -> bool {
+        self.inner.is_ready()
+    }
+    #[napi(js_name = "warmupPeriod")]
+    pub fn warmup_period(&self) -> u32 {
+        self.inner.warmup_period() as u32
+    }
+}
+
+// Open-interest momentum: rate-of-change of open interest over a window.
+#[napi(js_name = "OpenInterestMomentum")]
+pub struct OpenInterestMomentumNode {
+    inner: wc::OpenInterestMomentum,
+}
+
+#[napi]
+impl OpenInterestMomentumNode {
+    #[napi(constructor)]
+    pub fn new(period: u32) -> napi::Result<Self> {
+        Ok(Self {
+            inner: wc::OpenInterestMomentum::new(period as usize).map_err(map_err)?,
+        })
+    }
+    #[napi]
+    pub fn update(&mut self, open_interest: f64) -> napi::Result<Option<f64>> {
+        Ok(self.inner.update(deriv_oi(open_interest)?))
+    }
+    #[napi]
+    pub fn batch(&mut self, open_interest: Vec<f64>) -> napi::Result<Vec<f64>> {
+        let mut out = Vec::with_capacity(open_interest.len());
+        for oi in open_interest {
+            out.push(self.inner.update(deriv_oi(oi)?).unwrap_or(f64::NAN));
+        }
+        Ok(out)
+    }
+    #[napi]
+    pub fn reset(&mut self) {
+        self.inner.reset();
+    }
+    #[napi(js_name = "isReady")]
+    pub fn is_ready(&self) -> bool {
+        self.inner.is_ready()
+    }
+    #[napi(js_name = "warmupPeriod")]
+    pub fn warmup_period(&self) -> u32 {
+        self.inner.warmup_period() as u32
+    }
+}
+
 // ---------- Market Breadth (CrossSection input) ----------
 //
 // A breadth tick is the per-symbol state of the whole universe, passed as four

bindings/python/python/wickra/__init__.py

@@ -480,6 +480,11 @@ from ._wickra import (
     # Microstructure: footprint
     Footprint,
     # Derivatives
+    OpenInterestMomentum,
+    FundingImpliedApr,
+    PerpetualPremiumIndex,
+    OiToVolumeRatio,
+    EstimatedLeverageRatio,
     FundingRate,
     FundingRateMean,
     FundingRateZScore,
@@ -998,6 +1003,11 @@ __all__ = [
     # Microstructure: footprint
     "Footprint",
     # Derivatives
+    "OpenInterestMomentum",
+    "FundingImpliedApr",
+    "PerpetualPremiumIndex",
+    "OiToVolumeRatio",
+    "EstimatedLeverageRatio",
     "FundingRate",
     "FundingRateMean",
     "FundingRateZScore",

bindings/python/src/lib.rs

@@ -19420,6 +19420,50 @@ fn deriv_taker(taker_buy_volume: f64, taker_sell_volume: f64) -> PyResult<wc::De
     .map_err(map_err)
 }
 
+fn deriv_oi_long_short(
+    open_interest: f64,
+    long_size: f64,
+    short_size: f64,
+) -> PyResult<wc::DerivativesTick> {
+    wc::DerivativesTick::new(
+        0.0,
+        1.0,
+        1.0,
+        1.0,
+        open_interest,
+        long_size,
+        short_size,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0,
+    )
+    .map_err(map_err)
+}
+
+fn deriv_oi_taker(
+    open_interest: f64,
+    taker_buy_volume: f64,
+    taker_sell_volume: f64,
+) -> PyResult<wc::DerivativesTick> {
+    wc::DerivativesTick::new(
+        0.0,
+        1.0,
+        1.0,
+        1.0,
+        open_interest,
+        0.0,
+        0.0,
+        taker_buy_volume,
+        taker_sell_volume,
+        0.0,
+        0.0,
+        0,
+    )
+    .map_err(map_err)
+}
+
 fn deriv_liquidation(
     long_liquidation: f64,
     short_liquidation: f64,
@@ -20140,6 +20184,302 @@ impl PyCalendarSpread {
     }
 }
 
+// Estimated leverage ratio: open interest over aggregate long+short size.
+#[pyclass(
+    name = "EstimatedLeverageRatio",
+    module = "wickra._wickra",
+    skip_from_py_object
+)]
+#[derive(Clone)]
+struct PyEstimatedLeverageRatio {
+    inner: wc::EstimatedLeverageRatio,
+}
+
+#[pymethods]
+impl PyEstimatedLeverageRatio {
+    #[new]
+    fn new() -> Self {
+        Self {
+            inner: wc::EstimatedLeverageRatio::new(),
+        }
+    }
+    fn update(
+        &mut self,
+        open_interest: f64,
+        long_size: f64,
+        short_size: f64,
+    ) -> PyResult<Option<f64>> {
+        Ok(self
+            .inner
+            .update(deriv_oi_long_short(open_interest, long_size, short_size)?))
+    }
+    fn batch<'py>(
+        &mut self,
+        py: Python<'py>,
+        open_interest: Vec<f64>,
+        long_size: Vec<f64>,
+        short_size: Vec<f64>,
+    ) -> PyResult<Bound<'py, PyArray1<f64>>> {
+        if open_interest.len() != long_size.len() || long_size.len() != short_size.len() {
+            return Err(PyValueError::new_err(
+                "open_interest, long_size, short_size must be equal length",
+            ));
+        }
+        let mut out = Vec::with_capacity(open_interest.len());
+        for i in 0..open_interest.len() {
+            out.push(
+                self.inner
+                    .update(deriv_oi_long_short(
+                        open_interest[i],
+                        long_size[i],
+                        short_size[i],
+                    )?)
+                    .unwrap_or(f64::NAN),
+            );
+        }
+        Ok(out.into_pyarray(py))
+    }
+    fn reset(&mut self) {
+        self.inner.reset();
+    }
+    fn is_ready(&self) -> bool {
+        self.inner.is_ready()
+    }
+    fn warmup_period(&self) -> usize {
+        self.inner.warmup_period()
+    }
+    fn __repr__(&self) -> String {
+        "EstimatedLeverageRatio()".to_string()
+    }
+}
+
+// OI-to-volume ratio: open interest over taker buy+sell volume.
+#[pyclass(
+    name = "OiToVolumeRatio",
+    module = "wickra._wickra",
+    skip_from_py_object
+)]
+#[derive(Clone)]
+struct PyOiToVolumeRatio {
+    inner: wc::OiToVolumeRatio,
+}
+
+#[pymethods]
+impl PyOiToVolumeRatio {
+    #[new]
+    fn new() -> Self {
+        Self {
+            inner: wc::OiToVolumeRatio::new(),
+        }
+    }
+    fn update(
+        &mut self,
+        open_interest: f64,
+        taker_buy_volume: f64,
+        taker_sell_volume: f64,
+    ) -> PyResult<Option<f64>> {
+        Ok(self.inner.update(deriv_oi_taker(
+            open_interest,
+            taker_buy_volume,
+            taker_sell_volume,
+        )?))
+    }
+    fn batch<'py>(
+        &mut self,
+        py: Python<'py>,
+        open_interest: Vec<f64>,
+        taker_buy_volume: Vec<f64>,
+        taker_sell_volume: Vec<f64>,
+    ) -> PyResult<Bound<'py, PyArray1<f64>>> {
+        if open_interest.len() != taker_buy_volume.len()
+            || taker_buy_volume.len() != taker_sell_volume.len()
+        {
+            return Err(PyValueError::new_err(
+                "open_interest, taker_buy_volume, taker_sell_volume must be equal length",
+            ));
+        }
+        let mut out = Vec::with_capacity(open_interest.len());
+        for i in 0..open_interest.len() {
+            out.push(
+                self.inner
+                    .update(deriv_oi_taker(
+                        open_interest[i],
+                        taker_buy_volume[i],
+                        taker_sell_volume[i],
+                    )?)
+                    .unwrap_or(f64::NAN),
+            );
+        }
+        Ok(out.into_pyarray(py))
+    }
+    fn reset(&mut self) {
+        self.inner.reset();
+    }
+    fn is_ready(&self) -> bool {
+        self.inner.is_ready()
+    }
+    fn warmup_period(&self) -> usize {
+        self.inner.warmup_period()
+    }
+    fn __repr__(&self) -> String {
+        "OiToVolumeRatio()".to_string()
+    }
+}
+
+// Perpetual premium index: relative premium of mark over index price.
+#[pyclass(
+    name = "PerpetualPremiumIndex",
+    module = "wickra._wickra",
+    skip_from_py_object
+)]
+#[derive(Clone)]
+struct PyPerpetualPremiumIndex {
+    inner: wc::PerpetualPremiumIndex,
+}
+
+#[pymethods]
+impl PyPerpetualPremiumIndex {
+    #[new]
+    fn new() -> Self {
+        Self {
+            inner: wc::PerpetualPremiumIndex::new(),
+        }
+    }
+    fn update(&mut self, mark_price: f64, index_price: f64) -> PyResult<Option<f64>> {
+        Ok(self.inner.update(deriv_basis(mark_price, index_price)?))
+    }
+    fn batch<'py>(
+        &mut self,
+        py: Python<'py>,
+        mark_price: Vec<f64>,
+        index_price: Vec<f64>,
+    ) -> PyResult<Bound<'py, PyArray1<f64>>> {
+        if mark_price.len() != index_price.len() {
+            return Err(PyValueError::new_err(
+                "mark_price and index_price must be equal length",
+            ));
+        }
+        let mut out = Vec::with_capacity(mark_price.len());
+        for i in 0..mark_price.len() {
+            out.push(
+                self.inner
+                    .update(deriv_basis(mark_price[i], index_price[i])?)
+                    .unwrap_or(f64::NAN),
+            );
+        }
+        Ok(out.into_pyarray(py))
+    }
+    fn reset(&mut self) {
+        self.inner.reset();
+    }
+    fn is_ready(&self) -> bool {
+        self.inner.is_ready()
+    }
+    fn warmup_period(&self) -> usize {
+        self.inner.warmup_period()
+    }
+    fn __repr__(&self) -> String {
+        "PerpetualPremiumIndex()".to_string()
+    }
+}
+
+// Funding-implied APR: per-interval funding annualised.
+#[pyclass(
+    name = "FundingImpliedApr",
+    module = "wickra._wickra",
+    skip_from_py_object
+)]
+#[derive(Clone)]
+struct PyFundingImpliedApr {
+    inner: wc::FundingImpliedApr,
+}
+
+#[pymethods]
+impl PyFundingImpliedApr {
+    #[new]
+    fn new(intervals_per_year: f64) -> PyResult<Self> {
+        Ok(Self {
+            inner: wc::FundingImpliedApr::new(intervals_per_year).map_err(map_err)?,
+        })
+    }
+    fn update(&mut self, funding_rate: f64) -> PyResult<Option<f64>> {
+        Ok(self.inner.update(deriv_funding(funding_rate)?))
+    }
+    fn batch<'py>(
+        &mut self,
+        py: Python<'py>,
+        funding_rate: Vec<f64>,
+    ) -> PyResult<Bound<'py, PyArray1<f64>>> {
+        let mut out = Vec::with_capacity(funding_rate.len());
+        for r in funding_rate {
+            out.push(self.inner.update(deriv_funding(r)?).unwrap_or(f64::NAN));
+        }
+        Ok(out.into_pyarray(py))
+    }
+    fn reset(&mut self) {
+        self.inner.reset();
+    }
+    fn is_ready(&self) -> bool {
+        self.inner.is_ready()
+    }
+    fn warmup_period(&self) -> usize {
+        self.inner.warmup_period()
+    }
+    fn __repr__(&self) -> String {
+        format!(
+            "FundingImpliedApr(intervals_per_year={})",
+            self.inner.intervals_per_year()
+        )
+    }
+}
+
+// Open-interest momentum: rate-of-change of open interest over a window.
+#[pyclass(
+    name = "OpenInterestMomentum",
+    module = "wickra._wickra",
+    skip_from_py_object
+)]
+#[derive(Clone)]
+struct PyOpenInterestMomentum {
+    inner: wc::OpenInterestMomentum,
+}
+
+#[pymethods]
+impl PyOpenInterestMomentum {
+    #[new]
+    fn new(period: usize) -> PyResult<Self> {
+        Ok(Self {
+            inner: wc::OpenInterestMomentum::new(period).map_err(map_err)?,
+        })
+    }
+    fn update(&mut self, open_interest: f64) -> PyResult<Option<f64>> {
+        Ok(self.inner.update(deriv_oi(open_interest)?))
+    }
+    fn batch<'py>(
+        &mut self,
+        py: Python<'py>,
+        open_interest: Vec<f64>,
+    ) -> PyResult<Bound<'py, PyArray1<f64>>> {
+        let mut out = Vec::with_capacity(open_interest.len());
+        for oi in open_interest {
+            out.push(self.inner.update(deriv_oi(oi)?).unwrap_or(f64::NAN));
+        }
+        Ok(out.into_pyarray(py))
+    }
+    fn reset(&mut self) {
+        self.inner.reset();
+    }
+    fn is_ready(&self) -> bool {
+        self.inner.is_ready()
+    }
+    fn warmup_period(&self) -> usize {
+        self.inner.warmup_period()
+    }
+    fn __repr__(&self) -> String {
+        format!("OpenInterestMomentum(period={})", self.inner.period())
+    }
+}
+
 // ============================== Market Breadth ==============================
 //
 // Market-breadth indicators consume a `CrossSection`: one tick carrying the
@@ -25029,6 +25369,11 @@ fn _wickra(_py: Python<'_>, m: &Bound<'_, PyModule>) -> PyResult<()> {
     m.add_class::<PyLiquidationFeatures>()?;
     m.add_class::<PyTermStructureBasis>()?;
     m.add_class::<PyCalendarSpread>()?;
+    m.add_class::<PyEstimatedLeverageRatio>()?;
+    m.add_class::<PyOiToVolumeRatio>()?;
+    m.add_class::<PyPerpetualPremiumIndex>()?;
+    m.add_class::<PyFundingImpliedApr>()?;
+    m.add_class::<PyOpenInterestMomentum>()?;
     m.add_class::<PyAdvanceDecline>()?;
     m.add_class::<PyAdvanceDeclineRatio>()?;
     m.add_class::<PyAdVolumeLine>()?;

bindings/python/tests/test_new_indicators.py

@@ -4082,6 +4082,71 @@ def test_basis_indicators_streaming_equals_batch():
     assert _eq_nan(batch, streamed)
 
 
+def test_b16_derivatives_reference():
+    # Estimated leverage: oi / (long + short) = 200 / 100 = 2.
+    assert ta.EstimatedLeverageRatio().update(200.0, 60.0, 40.0) == pytest.approx(2.0)
+    # OI-to-volume: oi / (buy + sell) = 100 / 50 = 2.
+    assert ta.OiToVolumeRatio().update(100.0, 30.0, 20.0) == pytest.approx(2.0)
+    # Perpetual premium: (mark - index) / index = 0.5 / 100 = 0.005.
+    assert ta.PerpetualPremiumIndex().update(100.5, 100.0) == pytest.approx(0.005)
+    # Funding-implied APR: rate * intervals = 0.0001 * 1095 = 0.1095.
+    assert ta.FundingImpliedApr(1095.0).update(0.0001) == pytest.approx(0.1095)
+    # Open-interest momentum (period 2): warmup then ROC% = 100*(120-100)/100 = 20.
+    oim = ta.OpenInterestMomentum(2)
+    assert oim.update(100.0) is None
+    assert oim.update(110.0) is None
+    assert oim.update(120.0) == pytest.approx(20.0)
+
+
+def test_b16_derivatives_streaming_equals_batch():
+    n = 40
+    oi = np.array([1000.0 + 50.0 * math.sin(i * 0.3) for i in range(n)], dtype=np.float64)
+    long_sz = np.array([600.0 + 20.0 * math.cos(i * 0.2) for i in range(n)], dtype=np.float64)
+    short_sz = np.array([400.0 + 15.0 * math.sin(i * 0.4) for i in range(n)], dtype=np.float64)
+    buy = np.array([300.0 + 10.0 * math.sin(i * 0.5) for i in range(n)], dtype=np.float64)
+    sell = np.array([250.0 + 12.0 * math.cos(i * 0.35) for i in range(n)], dtype=np.float64)
+    index = np.array([100.0 + math.sin(i * 0.2) for i in range(n)], dtype=np.float64)
+    mark = np.array([index[i] + 0.05 * math.cos(i * 0.3) for i in range(n)], dtype=np.float64)
+    rate = np.array([0.0001 * math.sin(i * 0.3) for i in range(n)], dtype=np.float64)
+
+    # EstimatedLeverageRatio; update(open_interest, long_size, short_size).
+    batch = ta.EstimatedLeverageRatio().batch(oi, long_sz, short_sz)
+    streamer = ta.EstimatedLeverageRatio()
+    streamed = np.array(
+        [streamer.update(oi[i], long_sz[i], short_sz[i]) for i in range(n)], dtype=np.float64
+    )
+    assert batch.shape == (n,)
+    assert _eq_nan(batch, streamed)
+
+    # OiToVolumeRatio; update(open_interest, taker_buy_volume, taker_sell_volume).
+    batch = ta.OiToVolumeRatio().batch(oi, buy, sell)
+    streamer = ta.OiToVolumeRatio()
+    streamed = np.array(
+        [streamer.update(oi[i], buy[i], sell[i]) for i in range(n)], dtype=np.float64
+    )
+    assert _eq_nan(batch, streamed)
+
+    # PerpetualPremiumIndex; update(mark_price, index_price).
+    batch = ta.PerpetualPremiumIndex().batch(mark, index)
+    streamer = ta.PerpetualPremiumIndex()
+    streamed = np.array(
+        [streamer.update(mark[i], index[i]) for i in range(n)], dtype=np.float64
+    )
+    assert _eq_nan(batch, streamed)
+
+    # FundingImpliedApr; update(funding_rate).
+    batch = ta.FundingImpliedApr(1095.0).batch(rate)
+    streamer = ta.FundingImpliedApr(1095.0)
+    streamed = np.array([streamer.update(rate[i]) for i in range(n)], dtype=np.float64)
+    assert _eq_nan(batch, streamed)
+
+    # OpenInterestMomentum; update(open_interest).
+    batch = ta.OpenInterestMomentum(10).batch(oi)
+    streamer = ta.OpenInterestMomentum(10)
+    streamed = np.array([streamer.update(oi[i]) for i in range(n)], dtype=np.float64)
+    assert _eq_nan(batch, streamed)
+
+
 # --- Alt-Chart Bars ------------------------------------------------------
 
 

bindings/wasm/src/lib.rs

@@ -9933,6 +9933,50 @@ fn deriv_taker(
     .map_err(map_err)
 }
 
+fn deriv_oi_long_short(
+    open_interest: f64,
+    long_size: f64,
+    short_size: f64,
+) -> Result<wc::DerivativesTick, JsError> {
+    wc::DerivativesTick::new(
+        0.0,
+        1.0,
+        1.0,
+        1.0,
+        open_interest,
+        long_size,
+        short_size,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0,
+    )
+    .map_err(map_err)
+}
+
+fn deriv_oi_taker(
+    open_interest: f64,
+    taker_buy_volume: f64,
+    taker_sell_volume: f64,
+) -> Result<wc::DerivativesTick, JsError> {
+    wc::DerivativesTick::new(
+        0.0,
+        1.0,
+        1.0,
+        1.0,
+        open_interest,
+        0.0,
+        0.0,
+        taker_buy_volume,
+        taker_sell_volume,
+        0.0,
+        0.0,
+        0,
+    )
+    .map_err(map_err)
+}
+
 fn deriv_liquidation(
     long_liquidation: f64,
     short_liquidation: f64,
@@ -10256,6 +10300,195 @@ impl WasmCalendarSpread {
     }
 }
 
+// ---------- Estimated Leverage Ratio ----------
+
+#[wasm_bindgen(js_name = EstimatedLeverageRatio)]
+pub struct WasmEstimatedLeverageRatio {
+    inner: wc::EstimatedLeverageRatio,
+}
+
+impl Default for WasmEstimatedLeverageRatio {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+#[wasm_bindgen(js_class = EstimatedLeverageRatio)]
+impl WasmEstimatedLeverageRatio {
+    #[wasm_bindgen(constructor)]
+    pub fn new() -> WasmEstimatedLeverageRatio {
+        Self {
+            inner: wc::EstimatedLeverageRatio::new(),
+        }
+    }
+    pub fn update(
+        &mut self,
+        open_interest: f64,
+        long_size: f64,
+        short_size: f64,
+    ) -> Result<Option<f64>, JsError> {
+        Ok(self
+            .inner
+            .update(deriv_oi_long_short(open_interest, long_size, short_size)?))
+    }
+    pub fn reset(&mut self) {
+        self.inner.reset();
+    }
+    #[wasm_bindgen(js_name = isReady)]
+    pub fn is_ready(&self) -> bool {
+        self.inner.is_ready()
+    }
+    #[wasm_bindgen(js_name = warmupPeriod)]
+    pub fn warmup_period(&self) -> usize {
+        self.inner.warmup_period()
+    }
+}
+
+// ---------- OI-to-Volume Ratio ----------
+
+#[wasm_bindgen(js_name = OiToVolumeRatio)]
+pub struct WasmOiToVolumeRatio {
+    inner: wc::OiToVolumeRatio,
+}
+
+impl Default for WasmOiToVolumeRatio {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+#[wasm_bindgen(js_class = OiToVolumeRatio)]
+impl WasmOiToVolumeRatio {
+    #[wasm_bindgen(constructor)]
+    pub fn new() -> WasmOiToVolumeRatio {
+        Self {
+            inner: wc::OiToVolumeRatio::new(),
+        }
+    }
+    pub fn update(
+        &mut self,
+        open_interest: f64,
+        taker_buy_volume: f64,
+        taker_sell_volume: f64,
+    ) -> Result<Option<f64>, JsError> {
+        Ok(self.inner.update(deriv_oi_taker(
+            open_interest,
+            taker_buy_volume,
+            taker_sell_volume,
+        )?))
+    }
+    pub fn reset(&mut self) {
+        self.inner.reset();
+    }
+    #[wasm_bindgen(js_name = isReady)]
+    pub fn is_ready(&self) -> bool {
+        self.inner.is_ready()
+    }
+    #[wasm_bindgen(js_name = warmupPeriod)]
+    pub fn warmup_period(&self) -> usize {
+        self.inner.warmup_period()
+    }
+}
+
+// ---------- Perpetual Premium Index ----------
+
+#[wasm_bindgen(js_name = PerpetualPremiumIndex)]
+pub struct WasmPerpetualPremiumIndex {
+    inner: wc::PerpetualPremiumIndex,
+}
+
+impl Default for WasmPerpetualPremiumIndex {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+#[wasm_bindgen(js_class = PerpetualPremiumIndex)]
+impl WasmPerpetualPremiumIndex {
+    #[wasm_bindgen(constructor)]
+    pub fn new() -> WasmPerpetualPremiumIndex {
+        Self {
+            inner: wc::PerpetualPremiumIndex::new(),
+        }
+    }
+    pub fn update(&mut self, mark_price: f64, index_price: f64) -> Result<Option<f64>, JsError> {
+        Ok(self.inner.update(deriv_basis(mark_price, index_price)?))
+    }
+    pub fn reset(&mut self) {
+        self.inner.reset();
+    }
+    #[wasm_bindgen(js_name = isReady)]
+    pub fn is_ready(&self) -> bool {
+        self.inner.is_ready()
+    }
+    #[wasm_bindgen(js_name = warmupPeriod)]
+    pub fn warmup_period(&self) -> usize {
+        self.inner.warmup_period()
+    }
+}
+
+// ---------- Funding-Implied APR ----------
+
+#[wasm_bindgen(js_name = FundingImpliedApr)]
+pub struct WasmFundingImpliedApr {
+    inner: wc::FundingImpliedApr,
+}
+
+#[wasm_bindgen(js_class = FundingImpliedApr)]
+impl WasmFundingImpliedApr {
+    #[wasm_bindgen(constructor)]
+    pub fn new(intervals_per_year: f64) -> Result<WasmFundingImpliedApr, JsError> {
+        Ok(Self {
+            inner: wc::FundingImpliedApr::new(intervals_per_year).map_err(map_err)?,
+        })
+    }
+    pub fn update(&mut self, funding_rate: f64) -> Result<Option<f64>, JsError> {
+        Ok(self.inner.update(deriv_funding(funding_rate)?))
+    }
+    pub fn reset(&mut self) {
+        self.inner.reset();
+    }
+    #[wasm_bindgen(js_name = isReady)]
+    pub fn is_ready(&self) -> bool {
+        self.inner.is_ready()
+    }
+    #[wasm_bindgen(js_name = warmupPeriod)]
+    pub fn warmup_period(&self) -> usize {
+        self.inner.warmup_period()
+    }
+}
+
+// ---------- Open-Interest Momentum ----------
+
+#[wasm_bindgen(js_name = OpenInterestMomentum)]
+pub struct WasmOpenInterestMomentum {
+    inner: wc::OpenInterestMomentum,
+}
+
+#[wasm_bindgen(js_class = OpenInterestMomentum)]
+impl WasmOpenInterestMomentum {
+    #[wasm_bindgen(constructor)]
+    pub fn new(period: usize) -> Result<WasmOpenInterestMomentum, JsError> {
+        Ok(Self {
+            inner: wc::OpenInterestMomentum::new(period).map_err(map_err)?,
+        })
+    }
+    pub fn update(&mut self, open_interest: f64) -> Result<Option<f64>, JsError> {
+        Ok(self.inner.update(deriv_oi(open_interest)?))
+    }
+    pub fn reset(&mut self) {
+        self.inner.reset();
+    }
+    #[wasm_bindgen(js_name = isReady)]
+    pub fn is_ready(&self) -> bool {
+        self.inner.is_ready()
+    }
+    #[wasm_bindgen(js_name = warmupPeriod)]
+    pub fn warmup_period(&self) -> usize {
+        self.inner.warmup_period()
+    }
+}
+
 // ---------- Heikin-Ashi Oscillator ----------
 
 #[wasm_bindgen(js_name = HeikinAshiOscillator)]

crates/wickra-core/src/indicators/estimated_leverage_ratio.rs

@@ -0,0 +1,155 @@
+//! Estimated Leverage Ratio — open interest per unit of aggregate position size.
+
+use crate::derivatives::DerivativesTick;
+use crate::traits::Indicator;
+
+/// Estimated Leverage Ratio (ELR) — open interest relative to the aggregate
+/// long+short position size, a proxy for how leveraged outstanding positions are.
+///
+/// ```text
+/// ELR = open_interest / (long_size + short_size)
+/// ```
+///
+/// The classic estimated leverage ratio compares open interest (the notional of
+/// outstanding contracts) to the capital backing it. With the size fields of a
+/// [`DerivativesTick`] standing in for the position base, the ratio rises when a
+/// given pool of positions controls more open interest — i.e. when the market is
+/// running hotter leverage. Spikes in ELR mark crowded, fragile conditions where a
+/// move can cascade into liquidations; a falling ELR marks deleveraging.
+///
+/// The ratio is non-negative; a tick with zero aggregate size reports `0` rather
+/// than dividing by zero. It is stateless — each tick yields one value (no warmup).
+/// Each `update` is O(1).
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{DerivativesTick, Indicator, EstimatedLeverageRatio};
+///
+/// let mut indicator = EstimatedLeverageRatio::new();
+/// let tick = DerivativesTick::new(0.0001, 100.0, 100.0, 100.0, 1_000.0, 400.0, 600.0, 0.0, 0.0, 0.0, 0.0, 0).unwrap();
+/// let elr = indicator.update(tick).unwrap();
+/// assert!((elr - 1.0).abs() < 1e-12); // 1000 / (400 + 600)
+/// ```
+#[derive(Debug, Clone, Default)]
+pub struct EstimatedLeverageRatio {
+    ready: bool,
+}
+
+impl EstimatedLeverageRatio {
+    /// Construct a new Estimated Leverage Ratio. The indicator is parameter-free.
+    #[must_use]
+    pub const fn new() -> Self {
+        Self { ready: false }
+    }
+}
+
+impl Indicator for EstimatedLeverageRatio {
+    type Input = DerivativesTick;
+    type Output = f64;
+
+    fn update(&mut self, tick: DerivativesTick) -> Option<f64> {
+        let base = tick.long_size + tick.short_size;
+        let elr = if base > 0.0 {
+            tick.open_interest / base
+        } else {
+            0.0
+        };
+        self.ready = true;
+        Some(elr)
+    }
+
+    fn reset(&mut self) {
+        self.ready = false;
+    }
+
+    fn warmup_period(&self) -> usize {
+        1
+    }
+
+    fn is_ready(&self) -> bool {
+        self.ready
+    }
+
+    fn name(&self) -> &'static str {
+        "EstimatedLeverageRatio"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    fn tick(oi: f64, long: f64, short: f64) -> DerivativesTick {
+        DerivativesTick::new_unchecked(
+            0.0, 100.0, 100.0, 100.0, oi, long, short, 0.0, 0.0, 0.0, 0.0, 0,
+        )
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let e = EstimatedLeverageRatio::new();
+        assert_eq!(e.warmup_period(), 1);
+        assert_eq!(e.name(), "EstimatedLeverageRatio");
+        assert!(!e.is_ready());
+    }
+
+    #[test]
+    fn ratio_reference_value() {
+        let mut e = EstimatedLeverageRatio::new();
+        // 1000 / (400 + 600) = 1.0.
+        assert_relative_eq!(
+            e.update(tick(1_000.0, 400.0, 600.0)).unwrap(),
+            1.0,
+            epsilon = 1e-12
+        );
+    }
+
+    #[test]
+    fn higher_oi_raises_ratio() {
+        let mut e = EstimatedLeverageRatio::new();
+        let low = e.update(tick(1_000.0, 500.0, 500.0)).unwrap();
+        let high = e.update(tick(3_000.0, 500.0, 500.0)).unwrap();
+        assert!(high > low);
+    }
+
+    #[test]
+    fn zero_base_is_zero() {
+        let mut e = EstimatedLeverageRatio::new();
+        assert_relative_eq!(
+            e.update(tick(1_000.0, 0.0, 0.0)).unwrap(),
+            0.0,
+            epsilon = 1e-12
+        );
+    }
+
+    #[test]
+    fn ready_after_first_update() {
+        let mut e = EstimatedLeverageRatio::new();
+        assert!(!e.is_ready());
+        e.update(tick(1_000.0, 500.0, 500.0));
+        assert!(e.is_ready());
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut e = EstimatedLeverageRatio::new();
+        e.update(tick(1_000.0, 500.0, 500.0));
+        assert!(e.is_ready());
+        e.reset();
+        assert!(!e.is_ready());
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let ticks: Vec<DerivativesTick> = (0..40)
+            .map(|i| tick(1_000.0 + f64::from(i) * 10.0, 500.0, 500.0))
+            .collect();
+        let batch = EstimatedLeverageRatio::new().batch(&ticks);
+        let mut b = EstimatedLeverageRatio::new();
+        let streamed: Vec<_> = ticks.iter().map(|x| b.update(*x)).collect();
+        assert_eq!(batch, streamed);
+    }
+}

crates/wickra-core/src/indicators/funding_implied_apr.rs

@@ -0,0 +1,164 @@
+//! Funding-Implied APR — the per-interval funding rate annualised.
+
+use crate::derivatives::DerivativesTick;
+use crate::error::{Error, Result};
+use crate::traits::Indicator;
+
+/// Funding-Implied APR — the perpetual's per-interval funding rate scaled to an
+/// annualised rate.
+///
+/// ```text
+/// APR = funding_rate · intervals_per_year
+/// ```
+///
+/// Funding is paid in small per-interval amounts (commonly every 8 hours, i.e.
+/// `1095` intervals per year). Annualising it converts the headline funding number
+/// into the carry cost (or yield) of holding the position for a year, which is far
+/// easier to reason about and to compare against spot lending rates, basis trades,
+/// and other yields. A large positive APR means longs pay a steep carry to shorts
+/// (and vice versa) — the economic incentive behind cash-and-carry and
+/// funding-arbitrage strategies.
+///
+/// The output is a fraction (multiply by `100` for percent) and may be negative.
+/// It is stateless — each tick yields one value (no warmup). Each `update` is O(1).
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{DerivativesTick, Indicator, FundingImpliedApr};
+///
+/// // 0.01% per 8h funding -> 0.0001 * 1095 ≈ 10.95% APR.
+/// let mut indicator = FundingImpliedApr::new(1095.0).unwrap();
+/// let tick = DerivativesTick::new(0.0001, 100.0, 100.0, 100.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0).unwrap();
+/// let apr = indicator.update(tick).unwrap();
+/// assert!((apr - 0.1095).abs() < 1e-9);
+/// ```
+#[derive(Debug, Clone)]
+pub struct FundingImpliedApr {
+    intervals_per_year: f64,
+    ready: bool,
+}
+
+impl FundingImpliedApr {
+    /// Construct a Funding-Implied APR with the number of funding intervals per
+    /// year (e.g. `1095` for 8-hour funding, `365` for daily).
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::InvalidParameter`] if `intervals_per_year` is not finite
+    /// and positive.
+    pub fn new(intervals_per_year: f64) -> Result<Self> {
+        if !intervals_per_year.is_finite() || intervals_per_year <= 0.0 {
+            return Err(Error::InvalidParameter {
+                message: "intervals_per_year must be finite and positive",
+            });
+        }
+        Ok(Self {
+            intervals_per_year,
+            ready: false,
+        })
+    }
+
+    /// Configured intervals per year.
+    pub const fn intervals_per_year(&self) -> f64 {
+        self.intervals_per_year
+    }
+}
+
+impl Indicator for FundingImpliedApr {
+    type Input = DerivativesTick;
+    type Output = f64;
+
+    fn update(&mut self, tick: DerivativesTick) -> Option<f64> {
+        self.ready = true;
+        Some(tick.funding_rate * self.intervals_per_year)
+    }
+
+    fn reset(&mut self) {
+        self.ready = false;
+    }
+
+    fn warmup_period(&self) -> usize {
+        1
+    }
+
+    fn is_ready(&self) -> bool {
+        self.ready
+    }
+
+    fn name(&self) -> &'static str {
+        "FundingImpliedApr"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    fn tick(funding: f64) -> DerivativesTick {
+        DerivativesTick::new_unchecked(
+            funding, 100.0, 100.0, 100.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0,
+        )
+    }
+
+    #[test]
+    fn rejects_invalid_intervals() {
+        assert!(matches!(
+            FundingImpliedApr::new(0.0),
+            Err(Error::InvalidParameter { .. })
+        ));
+        assert!(matches!(
+            FundingImpliedApr::new(-1.0),
+            Err(Error::InvalidParameter { .. })
+        ));
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let f = FundingImpliedApr::new(1095.0).unwrap();
+        assert_relative_eq!(f.intervals_per_year(), 1095.0, epsilon = 1e-12);
+        assert_eq!(f.warmup_period(), 1);
+        assert_eq!(f.name(), "FundingImpliedApr");
+        assert!(!f.is_ready());
+    }
+
+    #[test]
+    fn apr_reference_value() {
+        let mut f = FundingImpliedApr::new(1095.0).unwrap();
+        assert_relative_eq!(f.update(tick(0.0001)).unwrap(), 0.1095, epsilon = 1e-9);
+    }
+
+    #[test]
+    fn negative_funding_is_negative_apr() {
+        let mut f = FundingImpliedApr::new(1095.0).unwrap();
+        assert!(f.update(tick(-0.0001)).unwrap() < 0.0);
+    }
+
+    #[test]
+    fn zero_funding_is_zero() {
+        let mut f = FundingImpliedApr::new(365.0).unwrap();
+        assert_relative_eq!(f.update(tick(0.0)).unwrap(), 0.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut f = FundingImpliedApr::new(1095.0).unwrap();
+        f.update(tick(0.0001));
+        assert!(f.is_ready());
+        f.reset();
+        assert!(!f.is_ready());
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let ticks: Vec<DerivativesTick> = (0..40)
+            .map(|i| tick(0.0001 * (f64::from(i) * 0.3).sin()))
+            .collect();
+        let batch = FundingImpliedApr::new(1095.0).unwrap().batch(&ticks);
+        let mut b = FundingImpliedApr::new(1095.0).unwrap();
+        let streamed: Vec<_> = ticks.iter().map(|x| b.update(*x)).collect();
+        assert_eq!(batch, streamed);
+    }
+}

crates/wickra-core/src/indicators/mod.rs

@@ -131,6 +131,7 @@ mod ema;
 mod empirical_mode_decomposition;
 mod engulfing;
 mod equivolume;
+mod estimated_leverage_ratio;
 mod even_better_sinewave;
 mod evening_doji_star;
 mod evwma;
@@ -156,6 +157,7 @@ mod fractal_chaos_bands;
 mod frama;
 mod fry_pan_bottom;
 mod funding_basis;
+mod funding_implied_apr;
 mod funding_rate;
 mod funding_rate_mean;
 mod funding_rate_zscore;
@@ -278,9 +280,11 @@ mod ob_imbalance_topn;
 mod obv;
 mod oi_delta;
 mod oi_price_divergence;
+mod oi_to_volume_ratio;
 mod oi_weighted;
 mod omega_ratio;
 mod on_neck;
+mod open_interest_momentum;
 mod opening_marubozu;
 mod opening_range;
 mod order_flow_imbalance;
@@ -295,6 +299,7 @@ mod pearson_correlation;
 mod percent_above_ma;
 mod percent_b;
 mod percentage_trailing_stop;
+mod perpetual_premium_index;
 mod pgo;
 mod piercing_dark_cloud;
 mod pin;
@@ -619,6 +624,7 @@ pub use ema::Ema;
 pub use empirical_mode_decomposition::EmpiricalModeDecomposition;
 pub use engulfing::Engulfing;
 pub use equivolume::{Equivolume, EquivolumeOutput};
+pub use estimated_leverage_ratio::EstimatedLeverageRatio;
 pub use even_better_sinewave::EvenBetterSinewave;
 pub use evening_doji_star::EveningDojiStar;
 pub use evwma::Evwma;
@@ -644,6 +650,7 @@ pub use fractal_chaos_bands::{FractalChaosBands, FractalChaosBandsOutput};
 pub use frama::Frama;
 pub use fry_pan_bottom::FryPanBottom;
 pub use funding_basis::FundingBasis;
+pub use funding_implied_apr::FundingImpliedApr;
 pub use funding_rate::FundingRate;
 pub use funding_rate_mean::FundingRateMean;
 pub use funding_rate_zscore::FundingRateZScore;
@@ -766,9 +773,11 @@ pub use ob_imbalance_topn::OrderBookImbalanceTopN;
 pub use obv::Obv;
 pub use oi_delta::OpenInterestDelta;
 pub use oi_price_divergence::OIPriceDivergence;
+pub use oi_to_volume_ratio::OiToVolumeRatio;
 pub use oi_weighted::OIWeighted;
 pub use omega_ratio::OmegaRatio;
 pub use on_neck::OnNeck;
+pub use open_interest_momentum::OpenInterestMomentum;
 pub use opening_marubozu::OpeningMarubozu;
 pub use opening_range::{OpeningRange, OpeningRangeOutput};
 pub use order_flow_imbalance::OrderFlowImbalance;
@@ -783,6 +792,7 @@ pub use pearson_correlation::PearsonCorrelation;
 pub use percent_above_ma::PercentAboveMa;
 pub use percent_b::PercentB;
 pub use percentage_trailing_stop::PercentageTrailingStop;
+pub use perpetual_premium_index::PerpetualPremiumIndex;
 pub use pgo::Pgo;
 pub use piercing_dark_cloud::PiercingDarkCloud;
 pub use pin::Pin;
@@ -1478,6 +1488,11 @@ pub const FAMILIES: &[(&str, &[&str])] = &[
             "LiquidationFeatures",
             "TermStructureBasis",
             "CalendarSpread",
+            "EstimatedLeverageRatio",
+            "OiToVolumeRatio",
+            "PerpetualPremiumIndex",
+            "FundingImpliedApr",
+            "OpenInterestMomentum",
         ],
     ),
     (
@@ -1624,6 +1639,6 @@ mod family_tests {
         // the actual indicator count is the early-warning signal that an
         // indicator was added without being assigned a family.
         let total: usize = FAMILIES.iter().map(|(_, ns)| ns.len()).sum();
-        assert_eq!(total, 488, "FAMILIES total drifted from indicator count");
+        assert_eq!(total, 493, "FAMILIES total drifted from indicator count");
     }
 }

crates/wickra-core/src/indicators/oi_to_volume_ratio.rs

@@ -0,0 +1,154 @@
+//! OI-to-Volume Ratio — open interest relative to traded volume.
+
+use crate::derivatives::DerivativesTick;
+use crate::traits::Indicator;
+
+/// OI-to-Volume Ratio — open interest divided by the tick's total taker volume, a
+/// measure of how much position is *held* versus *turned over*.
+///
+/// ```text
+/// OIVR = open_interest / (taker_buy_volume + taker_sell_volume)
+/// ```
+///
+/// A high ratio means open interest dwarfs the volume trading it — positions are
+/// being held, not churned (low participation, potential complacency or a coiling
+/// market). A low ratio means heavy volume relative to outstanding interest —
+/// active churn, often around breakouts or capitulation. Watching the ratio change
+/// distinguishes new-money trends (OI and volume both rising) from short-covering
+/// or position rolls.
+///
+/// The ratio is non-negative; a tick with zero taker volume reports `0` rather than
+/// dividing by zero. It is stateless — each tick yields one value (no warmup). Each
+/// `update` is O(1).
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{DerivativesTick, Indicator, OiToVolumeRatio};
+///
+/// let mut indicator = OiToVolumeRatio::new();
+/// let tick = DerivativesTick::new(0.0, 100.0, 100.0, 100.0, 5_000.0, 0.0, 0.0, 400.0, 600.0, 0.0, 0.0, 0).unwrap();
+/// let oivr = indicator.update(tick).unwrap();
+/// assert!((oivr - 5.0).abs() < 1e-12); // 5000 / (400 + 600)
+/// ```
+#[derive(Debug, Clone, Default)]
+pub struct OiToVolumeRatio {
+    ready: bool,
+}
+
+impl OiToVolumeRatio {
+    /// Construct a new OI-to-Volume Ratio. The indicator is parameter-free.
+    #[must_use]
+    pub const fn new() -> Self {
+        Self { ready: false }
+    }
+}
+
+impl Indicator for OiToVolumeRatio {
+    type Input = DerivativesTick;
+    type Output = f64;
+
+    fn update(&mut self, tick: DerivativesTick) -> Option<f64> {
+        let volume = tick.taker_buy_volume + tick.taker_sell_volume;
+        let ratio = if volume > 0.0 {
+            tick.open_interest / volume
+        } else {
+            0.0
+        };
+        self.ready = true;
+        Some(ratio)
+    }
+
+    fn reset(&mut self) {
+        self.ready = false;
+    }
+
+    fn warmup_period(&self) -> usize {
+        1
+    }
+
+    fn is_ready(&self) -> bool {
+        self.ready
+    }
+
+    fn name(&self) -> &'static str {
+        "OiToVolumeRatio"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    fn tick(oi: f64, buy: f64, sell: f64) -> DerivativesTick {
+        DerivativesTick::new_unchecked(
+            0.0, 100.0, 100.0, 100.0, oi, 0.0, 0.0, buy, sell, 0.0, 0.0, 0,
+        )
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let o = OiToVolumeRatio::new();
+        assert_eq!(o.warmup_period(), 1);
+        assert_eq!(o.name(), "OiToVolumeRatio");
+        assert!(!o.is_ready());
+    }
+
+    #[test]
+    fn ratio_reference_value() {
+        let mut o = OiToVolumeRatio::new();
+        assert_relative_eq!(
+            o.update(tick(5_000.0, 400.0, 600.0)).unwrap(),
+            5.0,
+            epsilon = 1e-12
+        );
+    }
+
+    #[test]
+    fn more_volume_lowers_ratio() {
+        let mut o = OiToVolumeRatio::new();
+        let held = o.update(tick(5_000.0, 100.0, 100.0)).unwrap();
+        let churned = o.update(tick(5_000.0, 1_000.0, 1_000.0)).unwrap();
+        assert!(churned < held);
+    }
+
+    #[test]
+    fn zero_volume_is_zero() {
+        let mut o = OiToVolumeRatio::new();
+        assert_relative_eq!(
+            o.update(tick(5_000.0, 0.0, 0.0)).unwrap(),
+            0.0,
+            epsilon = 1e-12
+        );
+    }
+
+    #[test]
+    fn ready_after_first_update() {
+        let mut o = OiToVolumeRatio::new();
+        assert!(!o.is_ready());
+        o.update(tick(5_000.0, 100.0, 100.0));
+        assert!(o.is_ready());
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut o = OiToVolumeRatio::new();
+        o.update(tick(5_000.0, 100.0, 100.0));
+        assert!(o.is_ready());
+        o.reset();
+        assert!(!o.is_ready());
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let ticks: Vec<DerivativesTick> = (0..40)
+            .map(|i| tick(5_000.0, 100.0 + f64::from(i), 100.0))
+            .collect();
+        let batch = OiToVolumeRatio::new().batch(&ticks);
+        let mut b = OiToVolumeRatio::new();
+        let streamed: Vec<_> = ticks.iter().map(|x| b.update(*x)).collect();
+        assert_eq!(batch, streamed);
+    }
+}

crates/wickra-core/src/indicators/open_interest_momentum.rs

@@ -0,0 +1,221 @@
+//! Open-Interest Momentum — the rate of change of open interest over a lookback.
+
+use std::collections::VecDeque;
+
+use crate::derivatives::DerivativesTick;
+use crate::error::{Error, Result};
+use crate::traits::Indicator;
+
+/// Open-Interest Momentum — the percentage rate of change of open interest over a
+/// `period`-tick lookback.
+///
+/// ```text
+/// OIM = 100 · (OI_t − OI_{t−period}) / OI_{t−period}
+/// ```
+///
+/// Where [`OIDelta`](crate::OIDelta) reports the single-tick change in open
+/// interest, OI Momentum measures the trend in positioning over a window: positive
+/// values mean open interest is expanding (new money entering — a position build
+/// that fuels the prevailing move), negative values mean it is contracting
+/// (positions being closed — deleveraging or short-covering). Read alongside price:
+/// rising OI with rising price is a strong new-long trend, while rising price with
+/// falling OI is a short-covering rally on borrowed time.
+///
+/// The output is a percentage and may be negative. A zero base open interest
+/// `period` ticks ago reports `0` rather than dividing by zero. The first value
+/// lands after `period + 1` inputs. Each `update` is O(1).
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{DerivativesTick, Indicator, OpenInterestMomentum};
+///
+/// let mut indicator = OpenInterestMomentum::new(5).unwrap();
+/// let mut last = None;
+/// for i in 0..20 {
+///     let oi = 1_000.0 + f64::from(i) * 100.0;
+///     let tick = DerivativesTick::new(0.0, 100.0, 100.0, 100.0, oi, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0).unwrap();
+///     last = indicator.update(tick);
+/// }
+/// assert!(last.unwrap() > 0.0); // expanding OI
+/// ```
+#[derive(Debug, Clone)]
+pub struct OpenInterestMomentum {
+    period: usize,
+    window: VecDeque<f64>,
+    last: Option<f64>,
+}
+
+impl OpenInterestMomentum {
+    /// Construct an OI Momentum over a `period`-tick lookback.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::PeriodZero`] if `period == 0`.
+    pub fn new(period: usize) -> Result<Self> {
+        if period == 0 {
+            return Err(Error::PeriodZero);
+        }
+        Ok(Self {
+            period,
+            window: VecDeque::with_capacity(period + 1),
+            last: None,
+        })
+    }
+
+    /// Configured lookback period.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+
+    /// Current value if available.
+    pub const fn value(&self) -> Option<f64> {
+        self.last
+    }
+}
+
+impl Indicator for OpenInterestMomentum {
+    type Input = DerivativesTick;
+    type Output = f64;
+
+    fn update(&mut self, tick: DerivativesTick) -> Option<f64> {
+        if self.window.len() == self.period + 1 {
+            self.window.pop_front();
+        }
+        self.window.push_back(tick.open_interest);
+        if self.window.len() < self.period + 1 {
+            return None;
+        }
+        let base = *self.window.front().expect("non-empty");
+        let current = tick.open_interest;
+        let oim = if base > 0.0 {
+            100.0 * (current - base) / base
+        } else {
+            0.0
+        };
+        self.last = Some(oim);
+        Some(oim)
+    }
+
+    fn reset(&mut self) {
+        self.window.clear();
+        self.last = None;
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.period + 1
+    }
+
+    fn is_ready(&self) -> bool {
+        self.last.is_some()
+    }
+
+    fn name(&self) -> &'static str {
+        "OpenInterestMomentum"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    fn tick(oi: f64) -> DerivativesTick {
+        DerivativesTick::new_unchecked(
+            0.0, 100.0, 100.0, 100.0, oi, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0,
+        )
+    }
+
+    #[test]
+    fn rejects_zero_period() {
+        assert!(matches!(
+            OpenInterestMomentum::new(0),
+            Err(Error::PeriodZero)
+        ));
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let o = OpenInterestMomentum::new(5).unwrap();
+        assert_eq!(o.period(), 5);
+        assert_eq!(o.warmup_period(), 6);
+        assert_eq!(o.name(), "OpenInterestMomentum");
+        assert!(!o.is_ready());
+        assert_eq!(o.value(), None);
+    }
+
+    #[test]
+    fn first_emission_at_warmup_period() {
+        let mut o = OpenInterestMomentum::new(3).unwrap();
+        let ticks: Vec<DerivativesTick> = (0..6)
+            .map(|i| tick(1_000.0 + f64::from(i) * 100.0))
+            .collect();
+        let out = o.batch(&ticks);
+        for v in out.iter().take(3) {
+            assert!(v.is_none());
+        }
+        assert!(out[3].is_some());
+    }
+
+    #[test]
+    fn reference_value() {
+        // period 2: OI 1000 -> 1200 over the window -> +20%.
+        let mut o = OpenInterestMomentum::new(2).unwrap();
+        let out = o.batch(&[tick(1_000.0), tick(1_100.0), tick(1_200.0)]);
+        assert_relative_eq!(out[2].unwrap(), 20.0, epsilon = 1e-9);
+    }
+
+    #[test]
+    fn expanding_oi_is_positive() {
+        let mut o = OpenInterestMomentum::new(5).unwrap();
+        let ticks: Vec<DerivativesTick> = (0..20)
+            .map(|i| tick(1_000.0 + f64::from(i) * 100.0))
+            .collect();
+        let last = o.batch(&ticks).into_iter().flatten().last().unwrap();
+        assert!(last > 0.0);
+    }
+
+    #[test]
+    fn contracting_oi_is_negative() {
+        let mut o = OpenInterestMomentum::new(5).unwrap();
+        let ticks: Vec<DerivativesTick> = (0..20)
+            .map(|i| tick(3_000.0 - f64::from(i) * 100.0))
+            .collect();
+        let last = o.batch(&ticks).into_iter().flatten().last().unwrap();
+        assert!(last < 0.0);
+    }
+
+    #[test]
+    fn zero_base_is_zero() {
+        let mut o = OpenInterestMomentum::new(2).unwrap();
+        let out = o.batch(&[tick(0.0), tick(100.0), tick(200.0)]);
+        assert_relative_eq!(out[2].unwrap(), 0.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut o = OpenInterestMomentum::new(3).unwrap();
+        o.batch(
+            &(0..10)
+                .map(|i| tick(1_000.0 + f64::from(i) * 50.0))
+                .collect::<Vec<_>>(),
+        );
+        assert!(o.is_ready());
+        o.reset();
+        assert!(!o.is_ready());
+        assert_eq!(o.value(), None);
+        assert_eq!(o.update(tick(1_000.0)), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let ticks: Vec<DerivativesTick> = (0..80)
+            .map(|i| tick(1_000.0 + (f64::from(i) * 0.25).sin() * 300.0))
+            .collect();
+        let batch = OpenInterestMomentum::new(10).unwrap().batch(&ticks);
+        let mut b = OpenInterestMomentum::new(10).unwrap();
+        let streamed: Vec<_> = ticks.iter().map(|x| b.update(*x)).collect();
+        assert_eq!(batch, streamed);
+    }
+}

crates/wickra-core/src/indicators/perpetual_premium_index.rs

@@ -0,0 +1,139 @@
+//! Perpetual Premium Index — the perp mark price relative to spot.
+
+use crate::derivatives::DerivativesTick;
+use crate::traits::Indicator;
+
+/// Perpetual Premium Index — the perpetual's mark price relative to the spot index
+/// it tracks, as a fraction.
+///
+/// ```text
+/// premium = (mark_price − index_price) / index_price
+/// ```
+///
+/// A perpetual swap is pegged to spot by the funding mechanism, but it can still
+/// trade at a premium (above spot) or discount (below). A positive premium signals
+/// net long demand willing to pay up to hold the perp — bullish positioning, and
+/// the proximate driver of positive funding; a negative premium signals the
+/// reverse. Sustained extremes flag crowded positioning ripe for a funding-driven
+/// mean reversion.
+///
+/// The output is centred on zero and dimensionless (a fraction; multiply by `100`
+/// for percent). `index_price` is validated strictly positive on the tick, so the
+/// division is always defined. It is stateless — each tick yields one value (no
+/// warmup). Each `update` is O(1).
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{DerivativesTick, Indicator, PerpetualPremiumIndex};
+///
+/// let mut indicator = PerpetualPremiumIndex::new();
+/// // Mark 101 vs index 100 -> +1% premium.
+/// let tick = DerivativesTick::new(0.0, 101.0, 100.0, 101.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0).unwrap();
+/// let premium = indicator.update(tick).unwrap();
+/// assert!((premium - 0.01).abs() < 1e-12);
+/// ```
+#[derive(Debug, Clone, Default)]
+pub struct PerpetualPremiumIndex {
+    ready: bool,
+}
+
+impl PerpetualPremiumIndex {
+    /// Construct a new Perpetual Premium Index. The indicator is parameter-free.
+    #[must_use]
+    pub const fn new() -> Self {
+        Self { ready: false }
+    }
+}
+
+impl Indicator for PerpetualPremiumIndex {
+    type Input = DerivativesTick;
+    type Output = f64;
+
+    fn update(&mut self, tick: DerivativesTick) -> Option<f64> {
+        let premium = (tick.mark_price - tick.index_price) / tick.index_price;
+        self.ready = true;
+        Some(premium)
+    }
+
+    fn reset(&mut self) {
+        self.ready = false;
+    }
+
+    fn warmup_period(&self) -> usize {
+        1
+    }
+
+    fn is_ready(&self) -> bool {
+        self.ready
+    }
+
+    fn name(&self) -> &'static str {
+        "PerpetualPremiumIndex"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    fn tick(mark: f64, index: f64) -> DerivativesTick {
+        DerivativesTick::new_unchecked(0.0, mark, index, mark, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0)
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let p = PerpetualPremiumIndex::new();
+        assert_eq!(p.warmup_period(), 1);
+        assert_eq!(p.name(), "PerpetualPremiumIndex");
+        assert!(!p.is_ready());
+    }
+
+    #[test]
+    fn premium_reference_value() {
+        let mut p = PerpetualPremiumIndex::new();
+        assert_relative_eq!(p.update(tick(101.0, 100.0)).unwrap(), 0.01, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn discount_is_negative() {
+        let mut p = PerpetualPremiumIndex::new();
+        assert!(p.update(tick(99.0, 100.0)).unwrap() < 0.0);
+    }
+
+    #[test]
+    fn at_par_is_zero() {
+        let mut p = PerpetualPremiumIndex::new();
+        assert_relative_eq!(p.update(tick(100.0, 100.0)).unwrap(), 0.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn ready_after_first_update() {
+        let mut p = PerpetualPremiumIndex::new();
+        assert!(!p.is_ready());
+        p.update(tick(100.0, 100.0));
+        assert!(p.is_ready());
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut p = PerpetualPremiumIndex::new();
+        p.update(tick(101.0, 100.0));
+        assert!(p.is_ready());
+        p.reset();
+        assert!(!p.is_ready());
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let ticks: Vec<DerivativesTick> = (0..40)
+            .map(|i| tick(100.0 + (f64::from(i) * 0.3).sin(), 100.0))
+            .collect();
+        let batch = PerpetualPremiumIndex::new().batch(&ticks);
+        let mut b = PerpetualPremiumIndex::new();
+        let streamed: Vec<_> = ticks.iter().map(|x| b.update(*x)).collect();
+        assert_eq!(batch, streamed);
+    }
+}

crates/wickra-core/src/lib.rs

@@ -81,22 +81,23 @@ pub use indicators::{
     DoubleTopBottom, DownsideGapThreeMethods, Dpo, DragonflyDoji, DrawdownDuration, DumplingTop,
     Dx, DynamicMomentumIndex, EaseOfMovement, EffectiveSpread, EhlersStochastic, Ehma,
     ElderImpulse, ElderRay, ElderRayOutput, ElderSafeZone, ElderSafeZoneOutput, Ema,
-    EmpiricalModeDecomposition, Engulfing, Equivolume, EquivolumeOutput, EvenBetterSinewave,
+    EmpiricalModeDecomposition, Engulfing, Equivolume, EquivolumeOutput, EstimatedLeverageRatio,
-    EveningDojiStar, Evwma, EwmaVolatility, Expectancy, FallingThreeMethods, Fama, FibArcs,
+    EvenBetterSinewave, EveningDojiStar, Evwma, EwmaVolatility, Expectancy, FallingThreeMethods,
-    FibArcsOutput, FibChannel, FibChannelOutput, FibConfluence, FibConfluenceOutput, FibExtension,
+    Fama, FibArcs, FibArcsOutput, FibChannel, FibChannelOutput, FibConfluence, FibConfluenceOutput,
-    FibExtensionOutput, FibFan, FibFanOutput, FibProjection, FibProjectionOutput, FibRetracement,
+    FibExtension, FibExtensionOutput, FibFan, FibFanOutput, FibProjection, FibProjectionOutput,
-    FibRetracementOutput, FibTimeZones, FibTimeZonesOutput, FibonacciPivots, FibonacciPivotsOutput,
+    FibRetracement, FibRetracementOutput, FibTimeZones, FibTimeZonesOutput, FibonacciPivots,
-    FisherRsi, FisherTransform, FlagPennant, Footprint, FootprintOutput, ForceIndex,
+    FibonacciPivotsOutput, FisherRsi, FisherTransform, FlagPennant, Footprint, FootprintOutput,
-    FractalChaosBands, FractalChaosBandsOutput, Frama, FryPanBottom, FundingBasis, FundingRate,
+    ForceIndex, FractalChaosBands, FractalChaosBandsOutput, Frama, FryPanBottom, FundingBasis,
-    FundingRateMean, FundingRateZScore, GainLossRatio, GapSideBySideWhite, Garch11,
+    FundingImpliedApr, FundingRate, FundingRateMean, FundingRateZScore, GainLossRatio,
-    GarmanKlassVolatility, Gartley, GatorOscillator, GatorOscillatorOutput, GeneralizedDema,
+    GapSideBySideWhite, Garch11, GarmanKlassVolatility, Gartley, GatorOscillator,
-    GeometricMa, GoldenPocket, GoldenPocketOutput, GrangerCausality, GravestoneDoji, Hammer,
+    GatorOscillatorOutput, GeneralizedDema, GeometricMa, GoldenPocket, GoldenPocketOutput,
-    HangingMan, Harami, HaramiCross, HasbrouckInformationShare, HeadAndShoulders, HeikinAshi,
+    GrangerCausality, GravestoneDoji, Hammer, HangingMan, Harami, HaramiCross,
-    HeikinAshiOscillator, HeikinAshiOutput, HiLoActivator, HighLowIndex, HighLowRange, HighWave,
+    HasbrouckInformationShare, HeadAndShoulders, HeikinAshi, HeikinAshiOscillator,
-    HighpassFilter, Hikkake, HikkakeModified, HilbertDominantCycle, HistoricalVolatility, Hma,
+    HeikinAshiOutput, HiLoActivator, HighLowIndex, HighLowRange, HighWave, HighpassFilter, Hikkake,
-    HoltWinters, HomingPigeon, HtDcPhase, HtPhasor, HtPhasorOutput, HtTrendMode, HurstChannel,
+    HikkakeModified, HilbertDominantCycle, HistoricalVolatility, Hma, HoltWinters, HomingPigeon,
-    HurstChannelOutput, HurstExponent, Ichimoku, IchimokuOutput, IdenticalThreeCrows, InNeck,
+    HtDcPhase, HtPhasor, HtPhasorOutput, HtTrendMode, HurstChannel, HurstChannelOutput,
-    Inertia, InformationRatio, InitialBalance, InitialBalanceOutput, InstantaneousTrendline,
+    HurstExponent, Ichimoku, IchimokuOutput, IdenticalThreeCrows, InNeck, Inertia,
+    InformationRatio, InitialBalance, InitialBalanceOutput, InstantaneousTrendline,
     IntradayIntensity, IntradayMomentumIndex, IntradayVolatilityProfile,
     IntradayVolatilityProfileOutput, InverseFisherTransform, InvertedHammer, JarqueBera, Jma,
     JumpIndicator, KagiBars, KalmanHedgeRatio, KalmanHedgeRatioOutput, Kama, KaseDevStop,
@@ -112,12 +113,13 @@ pub use indicators::{
     MedianPrice, Mfi, Microprice, MidPoint, MidPrice, MinusDi, MinusDm, ModifiedMaStop,
     ModifiedMaStopOutput, Mom, MorningDojiStar, MorningEveningStar, MurreyMathLines,
     MurreyMathLinesOutput, Natr, NewHighsNewLows, NewPriceLines, Nrtr, NrtrOutput, Nvi,
-    OIPriceDivergence, OIWeighted, Obv, OmegaRatio, OnNeck, OpenInterestDelta, OpeningMarubozu,
+    OIPriceDivergence, OIWeighted, Obv, OiToVolumeRatio, OmegaRatio, OnNeck, OpenInterestDelta,
-    OpeningRange, OpeningRangeOutput, OrderBookImbalanceFull, OrderBookImbalanceTop1,
+    OpenInterestMomentum, OpeningMarubozu, OpeningRange, OpeningRangeOutput,
-    OrderBookImbalanceTopN, OrderFlowImbalance, OuHalfLife, OvernightGap, OvernightIntradayReturn,
+    OrderBookImbalanceFull, OrderBookImbalanceTop1, OrderBookImbalanceTopN, OrderFlowImbalance,
-    OvernightIntradayReturnOutput, PainIndex, PairSpreadZScore, PairwiseBeta, ParkinsonVolatility,
+    OuHalfLife, OvernightGap, OvernightIntradayReturn, OvernightIntradayReturnOutput, PainIndex,
-    PearsonCorrelation, PercentAboveMa, PercentB, PercentageTrailingStop, Pgo, PiercingDarkCloud,
+    PairSpreadZScore, PairwiseBeta, ParkinsonVolatility, PearsonCorrelation, PercentAboveMa,
-    Pin, PivotReversal, PlusDi, PlusDm, Pmo, PointAndFigureBars, PolarizedFractalEfficiency, Ppo,
+    PercentB, PercentageTrailingStop, PerpetualPremiumIndex, Pgo, PiercingDarkCloud, Pin,
+    PivotReversal, PlusDi, PlusDm, Pmo, PointAndFigureBars, PolarizedFractalEfficiency, Ppo,
     PpoHistogram, ProfitFactor, ProjectionBands, ProjectionBandsOutput, ProjectionOscillator, Psar,
     Pvi, Qqe, QqeOutput, Qstick, QuartileBands, QuartileBandsOutput, QuotedSpread, RSquared,
     RealizedSpread, RealizedVolatility, RecoveryFactor, RectangleRange, Reflex, RegimeLabel,

docs/README.md

@@ -8,7 +8,7 @@ That includes:
   [Python](https://docs.wickra.org/Quickstart-Python),
   [Node](https://docs.wickra.org/Quickstart-Node), and
   [WASM](https://docs.wickra.org/Quickstart-WASM).
-- A per-indicator deep dive for every one of the **488 indicators** across
+- A per-indicator deep dive for every one of the **493 indicators** across
   the sixteen families (Moving Averages, Momentum Oscillators, Trend &
   Directional, Price Oscillators, Volatility & Bands, Bands & Channels,
   Trailing Stops, Volume, Price Statistics, Ehlers / Cycle DSP, Pivots &

fuzz/fuzz_targets/indicator_update_derivatives.rs

@@ -10,11 +10,7 @@
 //! never panic, streaming or batched.
 
 use libfuzzer_sys::fuzz_target;
-use wickra_core::{
+use wickra_core::{BatchExt, CalendarSpread, DerivativesTick, EstimatedLeverageRatio, FundingBasis, FundingImpliedApr, FundingRate, FundingRateMean, FundingRateZScore, Indicator, LiquidationFeatures, LongShortRatio, OIPriceDivergence, OIWeighted, OiToVolumeRatio, OpenInterestDelta, OpenInterestMomentum, PerpetualPremiumIndex, TakerBuySellRatio, TermStructureBasis};
-    BatchExt, CalendarSpread, DerivativesTick, FundingBasis, FundingRate, FundingRateMean,
-    FundingRateZScore, Indicator, LiquidationFeatures, LongShortRatio, OIPriceDivergence,
-    OIWeighted, OpenInterestDelta, TakerBuySellRatio, TermStructureBasis,
-};
 
 #[inline(never)]
 fn drive<I>(make: impl Fn() -> I, ticks: &[DerivativesTick])
@@ -53,6 +49,11 @@ fuzz_target!(|data: &[u8]| {
     drive(TakerBuySellRatio::new, &ticks);
     drive(TermStructureBasis::new, &ticks);
     drive(CalendarSpread::new, &ticks);
+    drive(EstimatedLeverageRatio::new, &ticks);
+    drive(OiToVolumeRatio::new, &ticks);
+    drive(PerpetualPremiumIndex::new, &ticks);
+    drive(|| FundingImpliedApr::new(1095.0).unwrap(), &ticks);
+    drive(|| OpenInterestMomentum::new(14).unwrap(), &ticks);
 
     // LiquidationFeatures emits a struct, not an f64, so drive it directly.
     let mut liq = LiquidationFeatures::new();