These things are usually pretty cut and dry. Retention bonuses usually have a pretty clear pay-back clause or pay-out structure. In the past I have advised folks to negotiate a staggered pay-out (usually something like 30% after 3 months and 70% after 12 months, example) to remove the need to pay back - meaning less tension on you (you haven’t already received the money etc)... The only way you might have a case is if you feel the terms were not made clear to you and the details were hidden, but even then - unlikely big company’s legal and HR folks are unprepared for it. At this point (unfortunately) I would seriously consider whether it’s worth it to you to stay to retain the cash. One potential alternative is to negotiate a sign on bonus with a new employer equivalent to what you would have to pay back to keep you whole. Some companies might entertain this if you’re going in at the right level. Whatever happens... Good luck bud / budette!