# Polymarket USD

> pUSD — the collateral token used for all trading on Polymarket

**pUSD** (Polymarket USD) is the collateral token used for all trading on Polymarket. It's a standard ERC-20 token on Polygon, backed by USDC. The smart contract — which enables the withdrawal functionality — enforces the backing. No algorithmic peg, no fractional reserve.

<Note>
  **Day to day, nothing changes.** You load funds, see a balance, trade, and
  withdraw. pUSD is the technical settlement layer underneath the same
  experience you're used to.
</Note>

***

## Why pUSD

The protocol settles all trading activity in native USDC, providing a more capital efficient, scalable, and institutionally aligned settlement standard as the platform continues to grow.

pUSD is a standard ERC-20 wrapper that represents a USDC claim. Wrapping and unwrapping are enforced onchain by the `CollateralOnramp` and `CollateralOfframp` contracts.

***

## Key facts

|                |                         |
| -------------- | ----------------------- |
| Token standard | ERC-20                  |
| Network        | Polygon mainnet         |
| Decimals       | 6                       |
| Backing        | USDC (enforced onchain) |
| Transferable   | Yes — standard ERC-20   |

pUSD is designed to function within Polymarket. There are no current plans to list it on external exchanges.

See the [Contracts](/resources/contracts) page for all collateral-related contract addresses.

***

## Wrapping — USDC.e → pUSD

Use the **CollateralOnramp** to wrap USDC.e into pUSD.

```solidity theme={null}
function wrap(address _asset, address _to, uint256 _amount) external
```

**Parameters**

* `_asset` — address of the asset being wrapped. Must be USDC.e.
* `_to` — recipient of the minted pUSD. Does not have to be `msg.sender`.
* `_amount` — amount to wrap, in USDC.e base units (6 decimals).

**Requirements**

* The caller must first approve the **CollateralOnramp** contract (not the pUSD token) to spend USDC.e.
* Reverts with `OnlyUnpaused()` if the admin has paused USDC.e.

### Example

<CodeGroup>
  ```typescript TypeScript theme={null}
  import {
    createWalletClient,
    createPublicClient,
    http,
    parseAbi,
    parseUnits,
  } from "viem";
  import { polygon } from "viem/chains";
  import { privateKeyToAccount } from "viem/accounts";

  const account = privateKeyToAccount(process.env.PRIVATE_KEY as `0x${string}`);
  const walletClient = createWalletClient({ account, chain: polygon, transport: http() });
  const publicClient = createPublicClient({ chain: polygon, transport: http() });

  const ONRAMP = "0x93070a847efEf7F70739046A929D47a521F5B8ee" as const;
  const USDCE = "0x2791Bca1f2de4661ED88A30C99A7a9449Aa84174" as const; // USDC.e on Polygon

  const amount = parseUnits("100", 6); // 100 USDC.e

  // 1. Approve the Onramp to spend your USDC.e
  const approveHash = await walletClient.writeContract({
    address: USDCE,
    abi: parseAbi(["function approve(address spender, uint256 amount) returns (bool)"]),
    functionName: "approve",
    args: [ONRAMP, amount],
  });
  await publicClient.waitForTransactionReceipt({ hash: approveHash });

  // 2. Wrap USDC.e → pUSD
  const wrapHash = await walletClient.writeContract({
    address: ONRAMP,
    abi: parseAbi(["function wrap(address _asset, address _to, uint256 _amount)"]),
    functionName: "wrap",
    args: [USDCE, account.address, amount],
  });
  await publicClient.waitForTransactionReceipt({ hash: wrapHash });
  ```

  ```python Python theme={null}
  from web3 import Web3

  ONRAMP = "0x93070a847efEf7F70739046A929D47a521F5B8ee"
  USDCE = "0x2791Bca1f2de4661ED88A30C99A7a9449Aa84174"

  amount = 100 * 10**6  # 100 USDC.e

  # 1. Approve the Onramp to spend your USDC.e
  usdce = w3.eth.contract(address=USDCE, abi=[{
      "name": "approve", "type": "function",
      "inputs": [{"name": "spender", "type": "address"},
                 {"name": "amount", "type": "uint256"}],
      "outputs": [{"type": "bool"}],
  }])
  usdce.functions.approve(ONRAMP, amount).transact({"from": address})

  # 2. Wrap USDC.e → pUSD
  onramp = w3.eth.contract(address=ONRAMP, abi=[{
      "name": "wrap", "type": "function",
      "inputs": [{"name": "_asset", "type": "address"},
                 {"name": "_to", "type": "address"},
                 {"name": "_amount", "type": "uint256"}],
      "outputs": [],
  }])
  onramp.functions.wrap(USDCE, address, amount).transact({"from": address})
  ```
</CodeGroup>

***

## Unwrapping — pUSD → USDC.e

Use the **CollateralOfframp** to unwrap pUSD back into USDC.e.

```solidity theme={null}
function unwrap(address _asset, address _to, uint256 _amount) external
```

**Parameters**

* `_asset` — asset you want to receive. Must be USDC.e.
* `_to` — recipient of the underlying asset.
* `_amount` — amount of pUSD to unwrap (6 decimals).

**Requirements**

* The caller must first approve the **CollateralOfframp** contract to spend their pUSD.
* Same pause gate as the Onramp.

***

## Next steps

<CardGroup cols={2}>
  <Card title="Contracts" icon="file-contract" href="/resources/contracts">
    All Polymarket contract addresses and audits
  </Card>

  <Card title="Bridge" icon="arrow-right-arrow-left" href="/trading/bridge/deposit">
    Deposit from other chains — auto-wraps to pUSD
  </Card>
</CardGroup>