Infusions of government cash that warded off an economic calamity have left millions of households with bigger bank balances than before the pandemic — savings that have driven a torrent of consumer spending, helped pay off debts and, at times, reduced the urgency of job hunts.

But many low-income Americans find their savings dwindling or even depleted.

And for them, the economic recovery is looking less buoyant.

Over the past 18 months or so, experts have been closely tracking the multitrillion-dollar increase in what economists call “excess savings,” generally defined as the amount by which people’s cash reserves during the COVID-19 crisis exceeded what they would have normally saved.

According to Moody’s Analytics, an economic research firm, these excess savings among many working- and middle-class households could be exhausted as soon as early next year — not only reducing their financial cushions but also potentially affecting the economy, since consumer spending is such a large share of activity.

Additionally, many pandemic-era federal programs expired in September, including the federal supplement to unemployment benefits.

In April 2020, after the pandemic’s outset, the nation’s personal saving rate — the percentage of overall disposable income that goes into savings each month — jumped fourfold from its February 2020 level to 34 percent.

Some of that spike in savings resulted from government checks of up to $1,200 sent to most Americans; some simply stemmed from reduced spending by firmly middle-class or a±uent households during lockdowns.

The rate peaked again at 26 percent in the spring after another round of direct federal payments.

But the personal saving rate does not account for how those savings are distributed. Wealthy households, for instance, have saved the most.

“We do tend to see these broad-brushstroke economic figures and assume that they apply to the broadest part of the populace,” said Mark Hamrick, senior economic analyst at Bankrate, a personal finance company. “There’s a significant cross-section of the American public which is financially fragile.”

New research by the JPMorgan Chase Institute, which assesses the bank accounts of 1.6 million families, found that low-income families experienced the “greatest percent gains” during each round of stimulus, yet also exhausted their balances faster.

That is in part because those households went into the crisis with the thinnest financial buffers.

The median balance among higher-income families (defined as those earning more than $68,896) was roughly 40 percent higher in September than two years earlier.

The typical low-income family (those earning less than $30,296) experienced a much larger increase in relative terms — 70 percent — but that represented a total cash balance of only about $1,000.

And households making $30,296 to $44,955 also made significant gains compared with 2019, yet typically had less than about $1,300 in cash on hand.

In a silver lining, the report found that the cash balances of families with children appear to have been helped by the three rounds of monthly child tax credit payments that began in July, which provided up to $300 per child younger than 6 and up to $250 per child 6-17.