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Merging is the inverse of splitting — it converts a full set of outcome tokens back into USDC.e collateral. For every 1 Yes token and 1 No token you merge, you receive $1 USDC.e. The condition must already be prepared on the CTF contract (via prepareCondition). 
100 Yes tokens + 100 No tokens → $100 USDC.e

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Prerequisites

Before merging, you need:
  1. Equal amounts of both Yes and No tokens
  2. Condition ID of the market
  3. Sufficient gas for the transaction

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How It Works

  1. You call mergePositions() with the amount and market details
  2. One unit of each position in a full set is burned in return for 1 collateral unit
  3. The CTF contract releases USDC.e back to your wallet
The operation is atomic — if you don’t have enough of both tokens, the transaction reverts.

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Function Parameters

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collateralToken
IERC20
USDC.e (Bridged USDC) contract address: 0x2791Bca1f2de4661ED88A30C99A7a9449Aa84174
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parentCollectionId
bytes32
Always 0x0000...0000 (32 zero bytes) for Polymarket markets
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conditionId
bytes32
The market’s condition ID, available from the Markets API
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partition
uint[]
Array of index sets: [1, 2] for binary markets
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amount
uint256
The number of full sets to merge. Also the amount of collateral to receive.

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Next Steps

Redeem Tokens

Exchange winning tokens for USDC.e after resolution

CTF Overview

Learn more about the Conditional Token Framework