Personally, I would be more concerned about something like determining whether the spread is more than a penny. Something like:

    if (ask - bid > 0.01) {
        // etc
    }

With floating point, I have to think about the following questions: * What if the constant 0.01 is actually slightly greater than mathematical 0.01? * What if the constant 0.01 is actually slightly less than mathematical 0.01? * What if ask - bid is actually slightly greater than the mathematical result? * What if ask - bid is actually slightly less than the mathematical result?

With floating point, that seemingly obvious code is anything but. With fixed point, you have none of those problems.

Granted, this only works for things that are priced in specific denominations (typically hundredths, thousandths, or ten thousandths), which is most securities.