The difference between mark to market and hold to maturity is an accounting difference to do with when profits and losses get realised. Secondly the rules about

The difference between mark to market and hold to maturity is an accounting difference to do with when profits and losses get realised. Secondly the rules about MTM vs HTM accounting tend to be dominated by whether or not there is a liquid market price for an asset (these are known as Level 1 mark to market assets), a liquid market price only for hedges or hedge equivalents of an asset (level 2) or whether a price has to be synthesised via a model (level 3, colloquially known as “mark to myth” during the crisis). There was a liquid market price for the vast majority of the assets in SVB’s portfolio. In any case P&L realisation wasn’t at all an issue relevant to the failure of SVB as I understand it. My understanding was that realising losses on swaps used to hedge their MBS portfolio led them to require more regulatory capital and when they mishandled communication during the raise, it failed leaving them essentially dead in the water. The next day all the VCs who had been in conversations about the raise told their portfolio cos to move funds out, those founders told their friends and SVB was a dead bank.