On September 17, the overnight Treasury repurchase agreement (repo) rate spiked to 6%—up from just 2.2% a week earlier and the highest level in more than 15 years (see DTCC GCF repo index). Oddly, this turmoil occurred at a time when the Fed had begun lowering its policy rate for the first time in more than a decade and market participants anticipated further policy easing ahead.

What led to this sudden disruption in short-term funding markets that been relatively calm in recent years? Had the Fed lost control? In our view, the explanation for the sudden rise in overnight interest rates is straightforward: the shrinkage of the Federal Reserve’s balance sheet that began in October 2017 reduced the aggregate supply of reserves gradually to where banks’ demand for reserves was insensitive to interest rates. Consequently, large temporary fluctuations in the supply of reserves that would have had virtually no impact even a few months ago, triggered sizable upward interest rate fluctuations.

Consistent with this view, the Federal Reserve recently took action to prevent a recurrence of the September disorder. At an unscheduled video conference meeting on October 11, the FOMC agreed to additional regular purchases of Treasury bills at least into the second quarter of 2020. The goal of this balance sheet expansion is to maintain reserve balances at least as high as their level in early-September before the turmoil began.

In the remainder of this post, we discuss the evolution of the supply and demand for reserves in recent years. We argue that, because no one—including the Fed—knew the precise level of reserves at which the demand curve would become inelastic, an episode like the one on September 17 was virtually inescapable as reserve supply declined. If our diagnosis of the cause is correct, then recent actions should help put the issue to rest. Yet, given the inevitability of the event―that the day would come when shrinking reserve supply hit the inelastic part of the reserve demand curve―the Fed could (and should) have been prepared. If so, it could have avoided even a temporary dent in its well-deserved reputation for operational prowess….

The Brave New World of Monetary Policy Operations

Prior to the Lehman failure in 2008, the Federal Reserve controlled the federal funds rate through open market operations that added to or subtracted from the excess reserves that banks held at the Fed. Because excess reserves typically were only a few billion dollars, the funds rate was very sensitive to small changes in the quantity of reserves in the system.

The Fed’s response to Lehman and its aftermath included large-scale asset purchases that led to a thousand-fold increase in excess reserves. Consequently, since 2008, small open-market operations of a few billion dollars no longer alter the federal funds rate. Instead, the Fed introduced administered rates to change its policy stance. The most important of these—the interest rate that the Fed now pays on excess reserves (IOER)—sets a floor below which banks will not lend to other counterparties (since an overnight loan to the Fed is the safest rate available).

Until very recently, the Fed’s ability to control the federal funds rate seemed well in hand….

Steve Cecchetti and Kim SchoenholtzJune 17, 2019Federal Reserve, FOMC, IOER, ON RRP, Standing repo facility, Federal funds rate, Federal funds rate target range, Monetary policy operations, SOFR, Excess reserves, Interest on excess reserves, Demand for reserves, Liquidity coverage ratio, LCR

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Money, Banking, and Financial Markets