Its assets may be worth more than its debt ... for now ... rising rates, customer withdrawals, future loan defaults, and mark-to-market valuation of assets could make any instituion insolvent at any time.
In 2008, it was NINJA loans, Collateralized Debt Obligations, and Credit Default Swaps - all risky private sector financial instruments constructed around Federally insured mortgages.
In 2023, it's 30 Year Treasury Bonds, so far - which is worse considering that US Treasury Bonds were considered to be the safest of safe assets.