PnL (Profit and Loss)

How we calculate the money a trader has made or lost on Polymarket.

Definition#

PnL measures total gains minus losses across all prediction market positions, including mark-to-market value of open positions at current prices. It answers the fundamental question: did this trader make money?

How It's Calculated#

For each position, we compute:

• Cost basis — the total USDC spent buying outcome tokens for this position (sum of all buy fills)
• Payout — for resolved markets, the terminal settlement (winning tokens pay $1, losing pay $0). For open markets, the current value of held tokens at live Gamma mid-prices (updated every 15 minutes).

A trader's total PnL is the sum across all their positions (resolved and open).

Worked Examples#

Profitable Trade#

Alice buys 100 “Yes” tokens at $0.60 each (cost = $60). The market resolves “Yes” — she receives $100. PnL = $100 − $60 = +$40.

Losing Trade#

Bob buys 200 “No” tokens at $0.35 each (cost = $70). The market resolves “Yes” — his “No” tokens are worth $0. PnL = $0 − $70 = −$70.

Multiple Positions#

Carol trades across 3 markets, netting +$120, −$45, and +$30. Her total PnL = $120 − $45 + $30 = +$105.

USDC Conversion#

All on-chain amounts are stored as raw integers in USDC (6 decimal places). We divide by 10⁶ to convert to human-readable dollar values. Since USDC is pegged 1:1 to USD, the displayed amounts are effectively in US dollars.

Cumulative PnL Chart#

The PnL chart on a trader's Analytics tab plots cumulative mark-to-market PnL over time. Snapshots are taken at 12-hour intervals (midnight and midday UTC), then aggregated to daily end-of-day values. The slope shows whether the trader is improving, declining, or flat.