Placing a Position

This page walks through the trade form and what happens when you submit a position.

The Trade Form

When you open a market's trading page, the trade form is on the right side. Here's what each element does:

Side Selector

Choose YES or NO. The selected side highlights in its respective color. The current market price for each side is shown next to the label.

Amount Input

Enter the USDC amount you want to spend. The form updates in real-time to show:

• Estimated tokens — How many outcome tokens you'll receive

• Effective price — Your average cost per token (accounting for price movement as your order fills)

• Fee — The total fee applied to your position (includes a dynamic LP fee + a flat 2% protocol fee)

Minimum Shares Protection

The contract includes slippage protection. When you submit a position, the transaction includes a minSharesOut parameter — the minimum number of tokens you're willing to accept. If the price moves unfavorably between your quote and execution, the transaction reverts instead of filling at a worse price.

Submitting a Position

First Time: USDC Approval

The first time you trade on a specific market, you need to approve USDC spending. This is a standard ERC-20 approval that allows the MarketEngine contract to transfer USDC from your wallet. You only need to do this once per market.

1. Click Approve USDC

2. Confirm the approval transaction in your wallet

3. Wait for confirmation (usually 1-2 seconds on Base)

4. The button changes to Place Position

Placing the Position

1. Click Place Position

2. Confirm the transaction in your wallet

3. The transaction processes on-chain

4. Your outcome tokens appear in the My Positions tab

After Your Position is Placed

Your tokens are standard ERC-20 tokens held in your wallet. You can see them in the My Positions tab on the trading page, which shows:

• Token type (YES or NO)

• Number of tokens held

• Your average cost basis

• Current market value

• Unrealized P&L

Position Limits

• Minimum position: 1.00 USDC

• Maximum position: Limited by pool liquidity and the skew cap (the contract prevents extreme one-sided imbalance)

Gas fees on Base are very low. A typical position costs less than 0.01 USDC in gas, so you don't need to worry about gas eating into small positions.