[lxgr]

It’s not a microsecond, it is zero seconds. The entire series of trades either succeeds as a bundle, or does not happen at all.

This is quite different from "normal" arbitrage, which consists of a series of non-atomic trades. There’s various risks here, both on the side of the arbitrageur (offer books can change, making the trade non-profitable halfway through) and by extension for all counterparties (due to the arbitrageur not being able to settle for the promised/borrowed amount), as well as non-zero time of locking up capital. Both have a price.