TYPPRICE computes the equal-weighted average of High, Low, and Close: $(H + L + C) \times \frac{1}{3}$. This three-component mean is the most widely used "representative price" in technical analysis, serving as the default input for CCI, MFI, and many other indicators. By including Close but excluding Open, Typical Price captures both the range extremes and the settlement point, giving slightly more weight to closing action than AVGPRICE does. The calculation is stateless and costs a single FMA instruction per bar.
## Historical Context
Typical Price became the standard price transform through its adoption by Donald Lambert in his 1980 Commodity Channel Index (CCI), which explicitly requires $(H+L+C)/3$ as its input. Gene Quong and Avrum Soudack used it in the Money Flow Index (MFI) in 1989. The TA-Lib function `TA_TYPPRICE` codified it as a standalone operation. TradingView exposes it as the `hlc3` built-in source selector.
The choice of three components rather than four is not arbitrary. Excluding Open removes the overnight gap component, which reflects news-driven repositioning rather than intra-session supply and demand. For intraday analysis, this makes Typical Price a purer measure of within-session fair value than AVGPRICE. For daily bars on instruments with significant gaps (equities, futures at session boundaries), the distinction matters; for 24-hour markets (forex, crypto), it is negligible.
In QuanTAlib, `TBar.HLC3` provides the same value as a zero-cost computed property. The `Typprice` indicator class wraps this in the streaming `ITValuePublisher` interface with bar correction, NaN safety, and event chaining.
Division by a non-power-of-two constant is 4-5x more expensive than multiplication on modern x86 CPUs (~15 cycles vs ~3 cycles). Precomputing $\frac{1}{3}$ as a `const double` and multiplying eliminates the division entirely. The compiler constant-folds `1.0 / 3.0` to the IEEE 754 double `0x3FD5555555555555` at compile time, so the hot path sees only multiply/FMA operations.
