Limit on Close (LOC) Order¶
A limit on close (LOC) order is a closing auction order that specifies a minimum acceptable execution price. The order participates in the 4:00 p.m. ET closing auction but fills only if the official auction price is at or better than the trader's limit — at or below for buys, at or above for sells. If the auction price does not satisfy the limit, the order expires unfilled.
HOW IT WORKS¶
LOC orders are submitted before exchange cutoff times — 3:45 p.m. ET on the NYSE, 3:50 p.m. ET on Nasdaq — and enter the closing auction alongside MOC orders and resting limit orders. The auction algorithm determines a single clearing price that maximizes matched shares. LOC orders with limits satisfied at that price receive fills; orders whose limits are not met expire at 4:00 p.m. ET with no execution and no impact on the auction price. Unlike a market on close (MOC) order, an LOC order offers price protection at the cost of fill certainty. A buy LOC at $100.00 does not fill if the auction clears at $100.01, even if the last regular-session trade printed at $100.00.
IN TAPEBOARD¶
Tapeboard surfaces the NYSE and Nasdaq imbalance feeds starting at 3:30 p.m. ET, giving traders real-time visibility into net auction direction before LOC deadlines pass. Use the imbalance panel to gauge whether the auction price is likely to satisfy your limit before committing the order. Tapeboard flags unfilled LOC orders in the order blotter at 4:00 p.m. ET and marks the resulting overnight exposure in the position summary, so traders can immediately assess gap risk on any position that failed to exit at the close.