That’s right. The trading desk also uses floats for analysis and regulatory reporting. Actual account balances come through an API that gives us floats, but rumor has it that it’s backed by Hollerith a punch card library maintained by cybernetic undead, encoded in 1215-EBCDIC-BLACKTONGUE.
(I do some work with predictive simulations about money, but outside finance, and there we care that the result has accurate order of magnitude. Floats were used extensively in the project; I actually upgraded them to doubles for the sake of handling larger order of magnitude spans.)