http://www.secinfo.com/dr6nd.818y.s.htm#1stPage
http://www.geekwire.com/2011/meet-shel-kaphan-amazoncom-empl...
"So, after five years were up — and my stock was all vested — I probably would have left a little earlier if that had not been the issue.
So, did you hang on to all of the shares because Amazon hit a rough patch just after you left?
“I don’t know what the effect on morale inside the company was since I wasn’t there. But I did do a lot of selling during those times, because from the outside, without knowing what was going on inside the company anymore, I didn’t know if it was going to be a casualty of that era or not, so I cashed out quite a bit of my position. But I did hold on to some of it, and I continue to.”"
Probably between 1 and 2%, I would guess. Some of which he cashed out when the stock was at a low. So between what his current shares are worth now and what he cashed out, probably at least $100 million.
EDIT: His foundation has $53 million in assets, so that should give an idea...
http://990s.foundationcenter.org/990pf_pdf_archive/651/65121...