How are very large options orders executed? I mean orders that are much larger than the current bid or ask size. For example, today someone bought 10,000 contracts of the Dec 12 115 Put for $4.80 at 11:04:41 on the ISE exchange with the underlying at 132.22. The bid/ask size for that strike is typically in the hundreds of contracts today. The market was 4.78 x 4.84 at the time of execution. Many thanks for any insight.