A market has the following limit orders standing on its book for a particular stock:
| Buyer | Bid Size (# of shares) | Limit Price($) | Seller | Offer Size (# of shares) | Limit Price($) |
| 1 | 500 | 18.50 | 1 | 200 | 20.20 |
| 2 | 300 | 18.90 | 2 | 300 | 20.35 |
| 3 | 400 | 19.20 | 3 | 400 | 20.50 |
| 4 | 200 | 20.10 | 4 | 100 | 20.65 |
| 5 | 100 | 20.15 | 5 | 200 | 20.70 |
If a trader submits an immediate-or-cancel limit buy order for 700 shares at a price of $20.50, the most likely average price the trader would pay is:
The limit buy order will be filled first with the most aggressively priced limit sell order and will be followed by filling with the higher priced limit sell orders that are needed up to and including the limit buy price until the order is filled.
Average price = [(200 x $20.20) + (300 x $20.35) + (200 x $20.50)] / 700 = $20.35.