An IPO pop is considered favorable versus the converse. You don't sell the whole company, so you still make money on the non-offered shares and you get an optic

An IPO pop is considered favorable versus the converse. You don't sell the whole company, so you still make money on the non-offered shares and you get an optically desirable price bump that can contribute to further positivity about the stock. Affirm priced around $12B (but now trades over $25B), yet they only raised about 10% of that. So yeah they left some money on the table but who's to say the stock would have generated such a pop if the IPO had priced higher? There's a lot of virtue in being long-term greedy, and sometimes that means leaving money on the table.