The prices of oil, transportation, food ingredients and other raw materials have fallen in recent months as the shocks stemming from the pandemic and the war in Ukraine have faded. Yet many big businesses have continued raising prices at a rapid clip.

Some of the world’s biggest companies have said they do not plan to change course and will continue increasing prices or keep them at elevated levels for the foreseeable future.

That strategy has cushioned corporate profits. And it could keep inflation robust, contributing to the very pressures used to justify surging prices.

As a result, some economists warn, policymakers at the Federal Reserve may feel compelled to keep raising interest rates, or at least not lower them, increasing the likelihood and severity of an economic downturn.

“Companies are not just maintaining margins, not just passing on cost increases, they have used it as a cover to expand margins,” Albert Edwards, a global strategist at Société Générale, said, referring to profit margins, a measure of how much businesses earn from every dollar of sales.

PepsiCo, the snacks and beverage maker, has become a prime example of how large corporations have countered increased costs, and then some.

Hugh Johnston, the company’s chief financial officer, said in February that PepsiCo had raised its prices by enough to buffer further cost pressures in 2023. At the end of April, the company reported that it had raised the average price across its products by 16 percent in the first three months of the year. That added to a similar size price increase in the fourth quarter of 2022 and increased its profit margin.

“I don’t think our margins are going to deteriorate at all,” Mr. Johnston said in a recent interview with Bloomberg TV. “In fact, what we’ve said for the year is we’ll be at least even with 2022, and may in fact increase margins during the course of the year.”

The bags of Doritos, cartons of Tropicana orange juice and bottles of Gatorade drinks sold by PepsiCo are now substantially pricier. Customers have grumbled, but they have largely kept buying. Shareholders have cheered. PepsiCo declined to comment.

PepsiCo is not alone in continuing to raise prices. Other companies that sell consumer goods have also done well.

The average company in the S&P 500 stock index increased its net profit margin from the end of last year, according to FactSet, a data and research firm, countering the expectations of Wall Street analysts that profit margins would decline slightly. And while margins are below their peak in 2021, analysts are forecasting that they will keep expanding in the second half of the year.

For much of the past two years, most companies “had a perfectly good excuse to go ahead and raise prices,” said Samuel Rines, an economist and the managing director of Corbu, a research firm that serves hedge funds and other investors. “Everybody knew that the war in Ukraine was inflationary, that grain prices were going up, blah, blah, blah. And they just took advantage of that.”

But those go-to rationales for elevating prices, he added, are now receding.

The Producer Price Index, which measures the prices businesses pay for goods and services before they are sold to consumers, reached a high of 11.7 percent last spring. That rate has plunged to 2.3 percent for the 12 months through April.

The Consumer Price Index, which tracks the prices of household expenditures on everything from eggs to rent, has also been falling, but at a much slower rate. In April, it dropped to 4.93 percent, from a high of 9.06 percent in June 2022. The price of carbonated drinks rose nearly 12 percent in April, over the previous 12 months.

“Inflation is going to stay much higher than it needs to be, because companies are being greedy,” Mr. Edwards of Société Générale said.

But analysts who distrust that explanation said there were other reasons consumer prices remained high. Since inflation spiked in the spring of 2021, some economists have made the case that as households emerged from the pandemic, demand for goods and services — whether garage doors or cruise trips — was left unsated because of lockdowns and constrained supply chains, driving prices higher.

David Beckworth, a senior research fellow at the right-leaning Mercatus Center at George Mason University and a former economist for the Treasury Department, said he was skeptical that the rapid pace of price increases was “profit-led.”

Corporations had some degree of cover for raising prices as consumers were peppered with news about imbalances in the economy. Yet Mr. Beckworth and others contend that those higher prices wouldn’t have been possible if people weren’t willing or able to spend more. In this analysis, stimulus payments from the government, investment gains, pay raises and the refinancing of mortgages at very low interest rates play a larger role in higher prices than corporate profit seeking.

“It seems to me that many telling the profit story forget that households have to actually spend money for the story to hold,” Mr. Beckworth said. “And once you look at the huge surge in spending, it becomes inescapable to me where the causality lies.”

Mr. Edwards acknowledged that government stimulus measures during the pandemic had an effect. In his eyes, this aid meant that average consumers weren’t “beaten up enough” financially to resist higher prices that might otherwise make them flinch. And, he added, this dynamic has also put the weight of inflation on poorer households “while richer ones won’t feel it as much.”

The top 20 percent of households by income typically account for about 40 percent of total consumer spending. Overall spending on recreational experiences and luxuries appears to have peaked, according to credit card data from large banks, but remains robust enough for firms to keep charging more. Major cruise lines, including Royal Caribbean, have continued lifting prices as demand for cruises has increased going into the summer.

Many people who are not at the top of the income bracket have had to trade down to cheaper products. As a result, several companies that cater to a broad customer base have fared better than expected, as well.

McDonald’s reported that its sales increased by an average of 12.6 percent per store for the three months through March, compared with the same period last year. About 4.2 percent of that growth has come from increased traffic and 8.4 percent from higher menu prices.

The company attributed the recent menu price increases to higher expenses for labor, transportation and meat. Several consumer groups have responded by pointing out that recent upticks in the cost of transportation and labor have eased.

A representative for the company said in an email that the company’s strong results were not just a result of price increases but also “strong consumer demand for McDonald’s around the world.”

Other corporations have found that fewer sales at higher prices have still helped them earn bigger profits: a dynamic that Mr. Rines of Corbu has coined “price over volume.”

Colgate-Palmolive, which in addition to commanding a roughly 40 percent share of the global toothpaste market, also sells kitchen soap and other goods, had a standout first quarter. Its operating profit for the year through March rose 6 percent from the same period a year earlier — the result of a 12 percent increase in prices even as volume declined by 2 percent.

The recent bonanza for corporate profits, however, may soon start to fizzle.

Research from Glenmede Investment Management indicates there are signs that more consumers are cutting back on pricier purchases. The financial services firm estimates that households in the bottom fourth by income will exhaust whatever is collectively left of their pandemic-era savings sometime this summer.

Some companies are beginning to find resistance from more price-sensitive customers. Dollar Tree reported rising sales but falling margins, as lower-income customers who tend to shop there searched for deals. Shares in the company plunged on Thursday as it cut back its profit expectations for the rest of the year. Even PepsiCo and McDonald’s have recently taken hits to their share prices as traders fear that they may not be able to keep increasing their profits.

For now, though, investors appear to be relieved that corporations did as well as they did in the first quarter, which has helped keep stock prices from falling broadly.

Before large companies began reporting how they did in the first three months of the year, the consensus among analysts was that earnings at companies in the S&P 500 would fall roughly 7 percent compared with the same period in 2022. Instead, according to data from FactSet, earnings are expected to have fallen around 2 percent once all the results are in.

Savita Subramanian, the head of U.S. equity and quantitative strategy at Bank of America, wrote in a note that the latest quarterly reports “once again showed corporate America’s ability to preserve margins.” Her team raised overall earnings growth expectations for the rest of the year, and 2024.