An employer may pay a bonus (or commission, etc.) early, then recover it if certain terms, goals, targets, etc. are not met. The issue is what was the terms of the bonus agreement--if the agreement required you to make certain numbers to get the bonus, then if when they gave you the bonus early, they did not change those terms, then the bonus is subject to recovery by your employer if you don't meet the goals. Whatever were the terms of the bonus are enforceable.If there were no qualitative terms for earning the bonus but rather it was discretionary, then once given, they should not be able to seek its recover.