From what I’ve read, they would have to mark the portfolio to market (i.e. report its value in terms of current market prices), not say “we intend to hold this to maturity” and account it at face value. Like, the latter actually makes more sense to me, but only if you actually don’t need to sell which might be true for a university endowment (all assets, no liabilities or at least very predictable liabilities) not for a hedging institution.