Was the accumulation duration larger than the regulatory mark-to-market period? As I understand it, SVG was heavy on US Treasuries, which lost a great deal of value due to recent interest rate hikes. As a result of a higher than expected deposit withdrawal rate, SVG sold US Treasuries for less than what they would have received if they had held them to maturity.

If the gap in finances was discovered earlier, would they have just converted more equities and other long-term higher-yeild instruments into treasuries and then go under because they couldn't get returns to match their deposit interest rates?

Had they been marking their holdings regularly they would have sold their depreciated holdings sooner when losses were smaller, instead of waiting until they had to to cover withdrawals.

Deposit interest is not fixed so that wouldn’t make them go under, they’d have to reduce their interest paid.