[kweinber]

I've had to do the math to calc this stuff... what you are saying is simply false. If I execute a single order with a full fill, and you execute the same fully filled order with 99 canceled order behind behind it, show me how the execution costs are "built in" to reflect the difference.

[kasey_junk]

They are built into the same way extra buttons you get with dress shirts are built in. Not everybody needs them, theoretically the people who don't use them are subsidizing the people that do, but no one cares. It is cheaper to deal with missing buttons as the norm than to build custom supply chains to optimize for correct distribution. If I called up the shirt manufacture and demanded 10K buttons on the other hand, they'd probably make me pay.

Finally, none of this has anything to do with spoofing, because spoofing doesn't need high cancel rates. If anything, making cancels more expensive will encourage the behavior, because it will make traditional market making more expensive (either explicitly or implicitly by requiring membership in a cartel to be a market maker). Meanwhile, the spoofers trade is much higher margin and can absorb the new extra cost more readily.