Yes, that’s another excuse that will inevitably be fielded: that those are “market” terms. It was tried in my case. Miraculously I ended up getting everything I wanted the moment I told them I was going to leave. Now, my negotiating position was unusually strong, and normally I wouldn’t get everything I wanted, but “market” is such a bullshit excuse in the case of early, core employees that it should be dismissed out of hand. Truly “market” terms are what you manage to negotiate. That having been said I didn’t actually request anything extraordinary.