I didn't know Sam was that loaded. Where did he get all that money from? I know he made some money back in the day, but I didn't think it was that high. Or he raised a fund or something?
IIRC YC's investment is 7%, correct? I'm not sure how much they participate in subsequent rounds, but Stripe alone is now valued at about $95 billion.
I'd be shocked if Sam weren't that loaded.
I recently saw an 8-figure round in which the lead put in $25K. But they did the legwork to arrange the round and get everyone else in, so they were the lead. Sam's the board chair, an early investor, and super connected, so he's certainly able to lead a round whether or not he puts in the majority of the cash.