Does California's final paycheck penalty apply to a final commission or bonus?

Commissions are treated as wages, and therefore fall under the final paycheck penalty rules, once they've been earned and can actually be calculated under the specific terms of your commission agreement. If a particular commission genuinely couldn't be calculated until sometime after you'd already left the job, the payment deadline runs from the point it became calculable, rather than from your actual last day.

Discretionary bonuses are typically treated differently and usually aren't considered wages under this framework at all. Because this distinction depends heavily on the exact language of your specific compensation agreement, it's worth reading that agreement carefully before assuming either commissions or bonuses fall one way or the other.