They took the deposits and bough "safe" bonds (eg treasuries). Which they're allowed to carry on their books at cost, even though their market price drops as interest rates rise.
But in both SVB and silvergates cases the drop in the market value of their assets coincided with an increase in withdrawals. They were forced to sell some of these bonds to fund withdrawals, requiring them to realize the market price. The accounting distorted the value of their assets to an extent, and the withdrawals laid that distortion bare
They took the deposits and bough "safe" bonds (eg treasuries). Which they're allowed to carry on their books at cost, even though their market price drops as interest rates rise.
But in both SVB and silvergates cases the drop in the market value of their assets coincided with an increase in withdrawals. They were forced to sell some of these bonds to fund withdrawals, requiring them to realize the market price. The accounting distorted the value of their assets to an extent, and the withdrawals laid that distortion bare