"SVB, for instance, found itself with some $16 billion in unrealized losses from long-dated Treasurys it held. As yields rose, it eroded the principle value of those bonds and created liquidity issues for the bank, long a favorite of high-flying tech investors that couldn’t get financing at traditional institutions. SVB had to sell those bonds at a loss to meet obligations."
https://www.cnbc.com/2023/03/14/moodys-cuts-outlook-on-us-banking-system-to-negative-citing-rapidly-deteriorating-operating-environment.html