Limit-on-Open Order

A Limit-on-Open (LOO) order is an order that specifies execution only at market open at the limit price or better. If the opening price is not at or within the limit price, the order is cancelled rather than remaining active during the trading session.

What Is a Limit-on-Open Order?

An LOO order combines the specificity of a limit order with the timing restriction of an “on-open” qualifier:
– The order must execute at the market open
– It will only execute at the specified limit price or a better price
– If the opening price is worse than the limit (e.g., stock opens below the sell limit), the order is cancelled

This is different from a standard limit order, which remains in the book throughout the session.

LOO vs Market-on-Open (MOO)

| Feature | LOO | MOO |
|———|—–|—–|
| Price control | Yes (limit price) | No (any opening price) |
| Execution certainty | Less certain | Guaranteed at opening price |
| Gap risk protection | Yes | No |

When Is LOO Used?

– Investors who want to respond to overnight news with price constraints at the open
– Traders who specifically want to enter or exit at the opening price but not at a dramatically gapped price
– Portfolio managers rebalancing index positions at open with price floor/ceiling requirements

LOO in India

Indian brokers may implement LOO-equivalent functionality through pre-market limit orders submitted during the pre-open session (9:00-9:08 AM). The equilibrium price determines the opening price; limit orders in the pre-open session that are not matched are typically cancelled or carried to regular session depending on broker rules.

Practical Example

An investor expects a stock to open higher due to overnight positive news. She places an LOO buy order at Rs 210 (current pre-market indication is Rs 215). If the stock opens at Rs 208 (below her limit), her order executes and she gets a better price. If it opens at Rs 220 (above her limit), her order is cancelled, as she does not want to chase the opening.

Key Takeaways

– LOO orders execute only at market open, at the limit price or better; otherwise cancelled
– Provides price control at the open unlike MOO (which executes at any opening price)
– Useful for traders who want open execution with a price floor or ceiling
– In India, pre-open session limit orders function similarly to LOO for equity stocks
– Not all brokers explicitly offer LOO as a named order type; it may be a configuration within pre-market order functionality