At Best

What Is At Best?

At-best is an instruction attached to an order to fill a transaction at the most desirable price available, and as quickly as possible.

At best orders are often market orders but may also entail a bit of discretion on the part of the broker to best execute the order.

Understanding At Best

At-best transactions can either be applied to equities or currencies where the trader would attempt to get the best possible price or rate respectively. At-best orders are generally executed faster than a conditional order, such as a limit order. The ultimate price a trader receives for a security is subject to the current market price, so the trader may wind up paying more (for a buy order) or receiving less (for a sell order) than expected.

At-best orders guarantee execution when there’s a willing counterparty for the entire order, but it doesn’t guarantee the price. Since you can’t set a price with at-best instructions, the actual price at which you may buy or sell may be higher or lower than expected. Thus, investors should be cautious when marking an order at-best unless they require immediate execution regardless of the price they receive.

When Is At Best... Best?

There are primarily two instances where an at-best order could come in handy, and which could not be further apart in motivation. In one case, at-best orders are useful for transactions requiring immediate execution while, on another hand, they can be useful for investors who require no immediacy whatsoever.

In the first instance, speed is of the essence and an at-best order makes sense for a strategy that requires immediate execution due to time-sensitive information. For example, when a trader realizes a profitable trade idea before anyone else does, and so wants to preempt other orders going the same way.

In the second example, and with quite the opposite end of the need for speed, certain long-term investors may simply mark an order at-best because they know they want to fill an order, but are unconcerned about price or immediacy. As an example, a hedge fund may want a certain asset class they're bullish on very long term, such as 20 years out, but doesn't feel the need to overpay for more expensive immediate execution. Here, they may simply say "buy it at whatever price" — as they know it won't matter given a long time horizon and a large expected price appreciation. In this case, the broker may construe the order as "not held", and work it at their discretion in order to get the best fill.