Sergeant Spoof's Time Has Passed

Spoofers.

Spoofing means putting in big buy (sell) orders that you don't intend to execute, with the intent to push the market price up (down), so that the smaller sell (buy) order that you do intend to execute can execute at a higher (lower) price than it otherwise would. It is bad and illegal and you shouldn't do it, and it has gotten increasing regulatory attention in recent years, and it is my sincere hope that at big banks these days the training program includes a module, or at least a sentence, on how you shouldn't spoof. But spoofing once got rather less regulatory attention, and in the not-too-distant past a lot of banks seem to have had training programs that instead covered how to spoof and how much fun it is.