What happens when you place an order: the lifecycle of a prediction market trade

What is the real difference between a market order and a limit order?

A market order executes immediately against the best offers on the book; a limit order sits on the orderbook at the price you set until someone accepts it. Practically, market orders trade execution certainty for price uncertainty, while limit orders trade price certainty for execution uncertainty.

Both order types can change the market’s implied probability because any matched trade removes liquidity and sets the last transaction price. Use market orders when speed matters and the size is small relative to visible liquidity; use limit orders when you care about the exact price or want to collect maker fees by providing liquidity.

How do market and limit orders affect price, matching, and my position?

Think of a market order as consuming existing orders and a limit order as posting one. A market buy takes the best ask(s) and may sweep multiple price levels if your size is larger than the available quantity; a limit buy becomes the new bid at your chosen price and only moves the visible best bid/ask when another trader accepts it.

Feature	Market order	Limit order
Where the order goes	Immediately consumes existing offers (the best ask for a buy)	Posts on the orderbook at your chosen price (becomes an offer or bid)
Execution speed	Immediate (subject to available liquidity)	May not execute; waits until matched or cancelled
Price control	Low — pays current asks, so you can suffer slippage	High — you set the price, no trade unless matched at that price or better
Effect on implied probability	Often moves price higher (if buying) because it removes asks	Moves price only when another trader takes your order; can shift the visible best bid/ask
Risk of partial fill	Higher for large market orders against thin books	Lower if another order accepts your full size; otherwise partial fills possible if matched in pieces
Typical fee role	Usually treated as taker (higher fee on many platforms)	Often treated as maker (lower fee), rewarding liquidity provision

A concrete example: if the best ask is 62¢ for a Yes contract that pays $1 if the event happens, buying one contract with a market order costs $0.62. If the event resolves Yes, the contract pays $1, so your gross gain before fees is $0.38; if the event resolves No, the contract pays $0 and your loss is $0.62.

What happens in my account the moment a trade matches?

When a match occurs, the market’s last-trade price updates immediately and the matched quantity is removed from the visible book. If your market order swept several price levels, you’ll notice the best ask move and spreads widen as liquidity is consumed.

You’ll receive an execution receipt listing quantity, executed price(s), fees, and time — this is your record. Platform accounting then updates: fees are calculated (often with a maker/taker split) and either deducted or shown; your balance, available margin, open position, and unrealized P&L reflect the trade instantly.

Settlement timing remains separate from matching: the contract stays live until the market resolves and settlement occurs according to the market’s rules (the $1 payout per winning Yes contract happens when the event reaches official resolution).

Why might a trade not fill, fill partially, or execute at a worse price than expected?

Partial fills happen when your requested size exceeds available liquidity at the matched price. Check the execution receipt to see the filled and remaining quantities; you can resubmit orders for the remainder or post a limit order to wait for more liquidity.

Slippage — price movement before execution — occurs when other traders remove liquidity faster than your order processes. To reduce slippage, use smaller chunks, a limit order, or split a large order across time; remember that a market order does not guarantee the price you think you’ll get.

Orders can also be cancelled or expire due to time-in-force settings, and markets can be paused or voided because of disputes, bad data, or resolution issues; platforms typically credit or refund affected positions and post notices. Insufficient balance is another common cause of rejection because fees or reserved margin reduce usable funds; top up or cancel outstanding reserved orders to free capital.

A frequent mistake is assuming a market order guarantees the intended price — if price certainty matters, use a limit order.

What terms on receipts and orderbooks should I know and when do they matter?

Receipt and orderbook labels you’ll see include Yes contract, bid, ask (offer), spread, fill/executed quantity, maker/taker, slippage, and settlement. Knowing whether your order was a maker or a taker explains fee differences; seeing executed price(s) and average cost explains your position and unrealized P&L.

Where each term fits practically: use market orders for immediate execution on deep books; use limit orders when price control or fee rebates matter. In thick markets with tiny spreads, the distinction often matters less because both order types will execute at virtually the same price. The differences become significant only when liquidity is thin or your order size is large relative to the book.

Where can I read more?

• What Are Prediction Markets?
• What Are Yes/No Contracts?
• How to Read Prediction Market Prices