At the end of 2022 the fund had $128.2 billion. I can't find a solid number on domestic deposits that are covered by FDIC based on the maximum deposit amount, but their Q2 2023 report showed $17.2 trillion in total domestic deposits across all FDIC institutions.

I'd expect that more than 0.7% of all deposits are under the $250k deposit limit. Let's just say 30% is actually covered, SVB had 89% of deposits above the limit when it failed, the insurance fund couldn't cover the failure of a bank with more than 3% of the market share of deposits.

The caveat there is that bank assets can be liquidated, but if the failure is fast enough that becomes really hairy. I haven't yet seen clear details on what strings they pulled and what sweetheart deals they gave when SVB was sold at the last minute, but that really means the fund isn't funded to cover enough and the hope really lies in market manipulation and a forced sale (likely funded in part by tax payers).