If so, it would mean that many predictions through the last several years of ultralow interest rates have misread the situation. “Once the economy gets going, then interest rates are going to take a big leap,” said George Soros, the billionaire hedge fund manager, in a 2013 CNBC interview.

“We can expect rapidly rising prices and much, much higher interest rates over the next four or five years,” wrote the economist Arthur B. Laffer in The Wall Street Journal in 2009. In 2014, all 67 economists surveyed by Bloomberg predicted higher rates six months later; they fell sharply instead.

Of course, rates could go up. But what that analysis may have missed is that interest rates historically are most closely tied to inflation. How much investors demand as compensation for lending their money is shaped in no small part by how much they think that money will be able to buy when they get it back. And the pressures that normally generate inflation seem to have disappeared in recent years.

The Fed and its counterparts overseas at the European Central Bank and Bank of Japan have spent the last few years applying every policy they can think of to get inflation to rise up to their 2 percent target, with limited success. In a world awash in supply of workers, oil and more, financial markets show little sign that investors think that will change anytime soon. Current Treasury bond prices predict annual inflation in the United States of only 1.7 percent a year over the next three decades.

That would imply that we are in an economic era more like the late 19th century, with persistent low inflation or mild deflation, or perhaps like the 1950s, when the economy was growing but inflation was firmly in check.

“If we keep inflation under control, maybe we’ll enter a period like the ’50s,” said Richard Sylla, a financial historian at New York University and co-author of “A History of Interest Rates.” “Those were normal rates, and they were accompanied by a slight amount of inflation, 1 or 2 percent. That worried people then, where now it’s a target to be reached.”