I Calculated Paul Graham's Net Worth

Your analysis is off. By a lot.

On paper, YC's companies are worth $600b & YC acquires 7% early on. But, that's before VCs like a16z, Sequoia, Softbank, etc. start investing say, $100M into single rounds, sometimes buying up to 25% of a startup in a single round of funding.

And YC companies take extremely long to get listed publicly (where Y Combinator can then offload most of their stock). Crunchbase says Airbnb went through 30 rounds of funding, Coinbase raised 20 times, and Doordash raised 13 times.

I know YC Continuity makes follow-on investments, but they're microscopic, compared to mainstream VCs. So, by the time a YC portfolio company goes public, Y Combinator probably owns 1%.

And then, we have to factor in that YC companies tend to disproportionately do badly after going public.

17 YC companies have gone public. 4 have gone to zero. 3 of lost 80% of their pre-IPO value. 8 others have lost 10% - 50%, while only Airbnb, Instacart, and Reddit have been positive. [0]

And I'll assume that YC can't sell stock right away, until after a lock-up period, which might expose them to further downside.

So, assuming YC owns 1% of their portfolio companies and we don't account for aggressive stock market losses (i.e.,), and PG owns 20% of YC, then he's worth roughly $1.2b - mostly in illiquid stock.

I bet PG can front $100M in a few hours, with a call to his bank, so he's not hurting for money. But, your analysis is off.

[0] https://www.marketsentiment.co/p/the-yc-report