The mechanism I'm trying to describe is when employers pay a base in X dollars and stock in Y dollars which takes Z years to mature. AWS sounds like they're being somewhat reasonable about it by giving an employee cash before their options mature, but I have interviewed at places (Envestnet in New York City) where I was offered a base comp which was meh and then options which were gonzo. The offer, if I remember correctly, was $105k/y base and then $100k/y in stock which took three years to vest. I passed on the offer because $105k/y in NYC was cutting it too close for me. They did not have a "cash float" mechanism.