The US Federal Reserve's role in America's string of bank failures

Many vulnerabilities were created by banks themselves but quantitative easing had an impact that must not be overlooked

- RAGHURAM G. RAJAN & VIRAL V. ACHARYA

The recent bank collapses in the US seem to have an obvious cause. About 90% of the deposits at Silicon Valley Bank (SVB) and Signature Bank were uninsured, and uninsured deposits are understandably prone to runs. Moreover, both banks had invested significant sums in long-term bonds, the market value of which fell as interest rates rose. When SVB sold some of these bonds to raise funds, the unrealized losses that were embedded in its bond portfolio started coming to light. A failed equity offering then set off the run on deposits that sealed its fate.

But four elements of this simple explanation suggest that the problem may be more systemic. First, there is typically a huge increase in uninsured bank deposits whenever the US Federal Reserve engages in quantitative easing (QE). Because it involves buying securities from the market in exchange for the central bank's own liquid reserves (a form of cash), QE not only increases the size of the central bank's balance sheet, but also drives an expansion in the broader banking system's balance sheet and its uninsured demandable deposits.