As I understand it, banks have some assets that are marked-to-market, and others that are assumed to be held to maturity. Their classification is determined whe

As I understand it, banks have some assets that are marked-to-market, and others that are assumed to be held to maturity. Their classification is determined when they are purchased, but there are rules governing the mix. To some degree this makes sense, because if the maturity timelines and classification are correct the bank is only losing opportunity cost and inflation-adjusted dollars. Not actual dollars. Meanwhile, if they need money from the fed it is offered against collateral based on mark-to-market value.