>notionally hedged against

on paper, SVB had protection from...

>...interest-rate duration risk

the danger that rising interest rates would mean it lost money on long term bonds at the historic (low) rate...

>...by this hold-to-maturity strategy,

using a common financial technique that valued the assets in question at their final value, not their current market value...

>that strategy put those assets outside the circle of those available to meet unexpected withdrawals

however, doing so meant those bonds weren't available if they needed immediate cash