So I’m really only making this post so I can link to it in another post, but while there have been plenty of explainers going around about what happened with Silicon Valley Bank (SVB) I wanted to get all the facts as I know them in one place.

Basically, Silicon Valley Bank had a bank run and needed a bailout. Why?

When you deposit your money into a bank, the bank pays you interest on the money. You are giving what is essentially a loan to the bank, and they in turn use that money to give loans to other people. The assumption is that the interest they get on their loans is more than the interest they pay you for your money, so the bank can always stay profitable.

Banks have their best relationships with the people who deposit money into them, so those tend to be the ones they reach out to and offer loans. Whatever bank you deposit your paycheck into is likely going to be the one that offers you a car or a house loan. But SVB was taking deposits from Tech startups and Silicon Valley hedge funds. Those guys don’t need or want loans. They raise money through equity, not loans. So while lots of deposits flowed into SVB, far fewer loans flowed out.

So how could SVB make money without loans? They bought bonds instead. Government bonds are just a loan you give to the government after all, and SVB thought that using their deposits to buy bonds was a surefire strategy because the government will never default. Remember that banks don’t ever just sit on loads of cash, they have to sell assets if they want “liquidity” (finance speak for cash). But if depositors want their money back, SVB can just sell bonds and give them cash, while if depositors hand them more money, SVB will use that money to buy government bonds.

But then inflation came, and brought with it interest rates. We’ve discussed before about how when interest rates rise, the price of an old bond falls. If you bought a bond paying 0.25% and interest rates have gone up to 5%, no one will buy your bond without a heavy discount. So 3 years ago a tech startup deposited $100 dollars into SVB, and SVB bought 100$ worth of bonds. Now the startup wants its money back but the 100$ bond SVB has bought has given them almost no interest (0.25%!) and has collapsed in price. When SVB sells its bond, it gets back WAY less than 100$.

So when interest rates rose, SVB’s bonds were all worth a lot less, but they were obligated to sell them to pay back their depositors. That would be fine if only a few depositors wanted their money, SVB can take a loss and make back the difference with profit elsewhere. But if ALL their depositors want their money back, SVB cannot cover.

And the depositors did want their money back. Startups backed by hedge funds get piles of money by selling stock, IPO’ing, and selling equity. Then they handed that money to SVB. Stock prices collapsed in part due to rising interest rates, the flow of cheap money stopped. Because of that, startups needed to take their money back out of SVB to keep the lights on. Money was flowing out but nothing was flowing in.

So SVB had a massive interest rates risk on both sides of its balance sheet. Interest rates decreased the amount of money going in (by tanking the stock market and making IPOs and share selling less common) while also decreasing the value of the assets SVB held (by making their government bonds worth less). Add onto that that inflation increased the amount of money flowing out (since startups needed to pay more for everything) and SVB was primed for a bank run. Depositors realized SVB didn’t have enough cash to cover everyone’s deposits, and so they all rushed to take all their money out before it collapsed.

And so collapse it did, and the government handed it a bailout. I’ll write more about that tomorrow.