Last trade price

Last trade price

Definition

The last trade price is the price of the most recent execution on a given instrument. On Polymarket this value reflects the price at which the most recent order fully or partially executed on the CLOB.

In context

You will encounter last trade price in real-time market feeds. Polymarket's Market WebSocket emits a last_trade_price event that reports this value for an instrument. Use it as a simple, time-ordered record of recent executions; it tells you what price counterparties were willing to trade at most recently, not the current depth of the book.

Because the last trade price is a single-point observation, it can move quickly on low-liquidity markets and during bursts of activity. Combine last_trade_price with best_bid_ask or the midpoint to understand whether the most recent trade happened at the bid, at the ask, or through the spread.

Practical notes

• On binary markets the last trade price is a number between 0.00 and 1.00 and should be interpreted as a probability-like price (e.g., 0.62 = $0.62). The sum of complementary binary outcome prices at fair value is $1.00, but an individual last trade price is simply the latest execution price for that outcome.
• Last trade price events are emitted alongside other WebSocket events such as price_change, best_bid_ask, and tick_size_change. The Market WebSocket sends a PING every 10 seconds; maintain the connection to continue receiving last_trade_price updates.
• Use last_trade_price for time-series charts, trade history displays, and simple alerts. For decision-making that depends on current liquidity or potential execution, always consult the order book via best_bid_ask or the midpoint.

See also

• /glossary/midpoint