[lsecondario]

> In theory

> At the extreme

> The theoretical model

These qualifiers would seem to belie the whole argument. Surely the volume of HFT arbitrage is some large multiple of what would be necessary to provide commercial liquidity with an acceptable spread?

[formerly_proven]

Does the HFT volume actually matter? Is it a real problem that the HFT volume exceeds the theoretical minimum amount of volume needed to maintain liquid markets?