Federal Reserve Chair Jerome Powell on Friday said a potential surge in U.S. coronavirus infections could derail the recovery from the deep downturn triggered by the pandemic, even as he reiterated the central bank’s vow to keep fighting the crisis.


The Fed has gone all out to steady financial markets since March, lowering borrowing costs and creating credit backstops for companies and local governments reeling from the economic fallout of lockdowns to stop the spread of the novel coronavirus.


More than 101,000 Americans have died from COVID-19, the respiratory illness caused by the virus, and many health officials are worried that infections could spike in the weeks and months ahead as states reopen their economies.


“I think a second wave would really undermine public confidence and might make for a significantly longer recovery and weaker recovery,” Powell said in a webcast with Alan Blinder, a Princeton University economics professor and former Fed vice chair.


Powell, a graduate of Princeton, spoke a few hours before his youngest daughter was to graduate from the Ivy League college.


“We of course would continue to react,” Powell said. “We are not close to any limits that we might have, I would say … but I would worry almost more that a second outbreak would undermine confidence.”


The remarks were a somber reminder that the trajectory of the crisis facing the Fed is a function of the public’s health, a factor over which the world’s most powerful central bank has no control.


The U.S. central bank has announced 11 programs to cushion the effects of the economic cratering, and all but two have come on line. The Fed is “days away from making our first loans” under the “Main Street Lending Program” to medium-sized companies, Powell said on Friday, and weeks from opening a lending program for states, counties and large cities.

The U.S. central bank now has a stake in the fortunes of a broad swath of corporate America after buying about $1.3 billion (1.06 billion pounds) of bond funds with debt issued by firms in all walks of the world’s biggest economy, from Apple Inc to a clutch of companies in bankruptcy.


The details on holdings in the Fed’s Secondary Market Corporate Credit Facility, one of nearly a dozen emergency programs the Fed has rolled out since March to respond to the coronavirus crisis, were published Friday.


The Fed’s largest investment-grade fund holding – iShares iBoxx US Dollar Investment Grade Corporate Bond ETF – contains 30 Apple bonds giving the Fed about $5.7 million of exposure to the maker of iPhones through that ETF alone as of May 19. Apple is also a holding in other ETFs the Fed bought.