WASHINGTON – Randy Graham, the chief executive of the First National Bank of Tennessee, was surprised to learn in mid-June that the Federal Reserve would not be filling his entire order of pennies, nickels, dimes and quarters.

The reason: The nation's coin supply was coming up short.

In the latest indication of how the coronavirus is disrupting life in unexpected ways, the flow of coins has become gummed up as consumers stayed home and avoided touching physical cash. In particular, customers have not been dumping their piggy banks into kiosks at grocery stores in exchange for bills.

As the country has begun to reopen, the supply of coins has failed to keep up with renewed demand for a type of currency that, even in an increasingly digital world, remains essential to business.

"Many businesses are dependent on the coin — they don't need the disruption," Graham said. He was told that his allocation would be cut drastically, to less than half of its usual total. Graham received about 40% of his usual order this week, and expects that to persist into early July.

"If this lasts any length of time, there's no question that we'll be looking at our customer base and saying, 'Sorry, don't have it,' " he said.

Even as digital payments become more of the norm in America, change remains crucial to some parts of the economy: Parking meters, vending machines, amusement parks and even campground showers have kept coins in regular use.

The U.S. Mint manufactures America's coins, and the Federal Reserve distributes them across the country. As typical coin circulation has been disrupted by the pandemic, those institutions have had to change their normal practices to solve the problem, with the Fed allocating coins to banks based on their historical order sizes and the Mint ramping up new coin shipments to pump fresh supply into the system.

"What's happened is that with the partial closure of the economy, the flow of coins through the economy … it's kind of stopped," Jerome Powell, the chair of the Fed, told lawmakers while testifying on Capitol Hill last week.

Treasury Secretary Steven Mnuchin said Tuesday that he believed the shortage would be solved. He noted that the staff at the Bureau of Engraving and Printing worked throughout the lockdown to ensure that cash was delivered to the Federal Reserve so it could be distributed to banks.

Precautionary cash hoarding has skyrocketed in some coronavirus-hit economies, including the United States and Italy, the Bank for International Settlements — a financial institution that serves central banks — found in a report out Wednesday. Even so, the institution suggested that the pandemic, which has also spurred an increase in contactless card transactions, could actually accelerate the shift toward digital payments.