At that time its assets were 158 b but the assets if Mark to Market is at a LOSS of 159 b. But per GAAP rule, these assets qualified to use the valuation method of Hold till Maturity. Indeed if these assets are held to maturity, the bank will get back 100% principal plus whatever interest earned based on the term.
Unfortunately due to the rapidly rising rates, its avg age of 3.6 year debts have lost a lot of value. When it is facing liquidity issue due to the IPO market literally is dead, the bank is forced to raise money.
At first it tried to sell its own shares as a secondary offering but apparently there was No Buyer. So it was forced to sell some of these assets - which of course would immediately become Mark to Market, and have Realized Loss to the tune of 1.8 b. Real Loss. It creates panic, and the VCs who funded the bank in the past now told their startups to withdraw money from the bank, created a huge bank run which no bank can survive, incl JPM or whoever.