If you read the SEC filings, there was a 12-13 billion hole in their balance sheet. The 1.8 was simply accounting rules which say they only have to recognize the giant hole when they sell and they sold some of the assets in question. Marked to market, ie assets marked to real prices instead of fantasy prices, they were toast.

People who looked at SVB financials knew it was a train wreck. They behaved like serious investment professionals and pulled their money.