A type of order that must be executed in its entirety or not at all. Unlike a partial fill, an AON order ensures the full quantity is filled at the specified price or better, or the order remains unfilled. AON orders are useful for traders dealing in illiquid markets or large block sizes who need to avoid the complications of partial fills.
Example
“I placed an all-or-none order for 10,000 shares because I didn't want to end up with a partial fill in this thinly traded stock.”