Market-on-Close (MOC) Order

A market-on-close (MOC) order is a market order set to execute as close as possible to the official market close. Traders use MOC orders to capture the closing price or to ensure a trade occurs at the end of the trading day without having to submit a market order exactly at the close.

Key takeaways

• MOC orders execute at or near the market’s official closing price.
• They become active only near market close and then behave like standard market orders.
• Exchanges set specific submission and cancellation deadlines for MOC orders.
• MOC orders guarantee execution at close timing but not the exact fill price.
• Risks include last-minute price swings and potential imbalances at the close.

How MOC orders work

1. Submission: You submit a MOC order during the trading day before the exchange’s cutoff time for such orders.
2. Dormant phase: The order remains inactive until the close.
3. Activation and execution: Near the end of trading, the order activates and is executed as a market order at or near the closing price.
4. Cancellation rules: Exchanges like the NYSE and Nasdaq impose deadlines and restrictions on when MOC orders can be canceled or modified.

Because MOC orders convert into market orders at the close, they do not specify a price. That makes them different from limit orders (which specify a minimum/maximum acceptable price) and similar in execution certainty to market orders, but with the specific timing of the close.

Typical uses

• Capture the official closing price for valuation, performance measurement, or index replication.
• Avoid holding a position overnight when material news (e.g., after-hours earnings) is expected.
• Execute trades when you cannot be available precisely at market close (time zone differences, scheduling).

Benefits

• Ensures execution at the market close rather than risking missed timing.
• Useful for strategies tied to end-of-day pricing (index funds, portfolio rebalancing, performance reporting).
• Convenient for traders who cannot trade at the exact close.

Risks and drawbacks

• Price uncertainty — the exact fill price is not guaranteed and can differ from the daytime trading price.
• End-of-day imbalances or thin liquidity can lead to wide spreads or poor execution.
• Large order flow at the close can amplify volatility and cause slippage.
• Exchange cutoffs mean you cannot always cancel or change the order at the last moment.

Example

A trader expects negative earnings news for company ABC after the market closes. To avoid holding the stock through an anticipated sell-off, the trader places a MOC sell order during the day. The order remains inactive until the close, then executes at the closing price, helping the trader exit before the after-hours announcement.

Best practices

• Know your broker’s and the exchange’s submission and cancellation cutoffs for MOC orders.
• Use MOC orders when your priority is the timing of the close rather than a specific price.
• Consider order size relative to typical close-day liquidity to reduce the risk of poor fills.
• If price certainty is important, consider alternatives such as limit-on-close orders (if supported) or placing limit orders earlier in the day.

Bottom line

MOC orders are a practical tool for executing trades at the market close, useful for end-of-day strategies and for avoiding overnight exposure. They guarantee execution timing but not price, and they carry risks tied to end-of-day liquidity and volatility. Use them intentionally, understanding exchange deadlines and how they fit into your overall trading plan.