The first fill can change the risk budget

The first fill arrives and the order is no longer hypothetical. Even a small fill can change what the rest of the plan means.

Exposure, cash, and attention have moved from the worksheet into the market.

Recalculate after the first match

Update filled size, average price, remaining quantity, and maximum loss immediately. Do not leave the original order size as if it were still the position.

A 20-share fill on a 100-share idea may create enough directional risk to change the next decision.

Check the concentration

Ask how the new position interacts with other open positions that share a source, event, or settlement date. The first fill can push a portfolio over a limit before the rest of the order executes.

Keep reserved cash and available cash separate when deciding whether to add another leg.

Give the remainder its own rule

Set a new price, time, and cancellation condition for the unfilled quantity. The market that filled the first piece may not be the market you face for the second.

The useful question is not how much of the original order remains. It is what the first fill changed about your risk budget and the next action.

Further reading: Prices and order books · Resolution rules · Current fees.

Explore the markets: Open Polymarket (referral link).