[jcranmer]

For starters, it's giving up a lot of performance, since fixed-point isn't accelerated by hardware like floating-point is.

[rendaw]

Isn't fixed point just integer?

[Athas]

Yes, but you're not going to have efficient transcendental functions implemented in hardware.

[rendaw]

Ah okay, fair enough. But what sort of transcendental functions would you use for HFT?

I guess I understood GGGGP's comment about using fixed point for interacting with currency to be about accounting. I'd expect floating point to be used for trading algorithms, but that's mostly statistics and I presume you'd switch back to fixed point before making trades etc.

[mitthrowaway2]

Yes, integer combined with bit-shifts.