The extent of and continuing increase in inequality in the United States greatly concerns me. … It is no secret that the past few decades of widening inequality can be summed up as significant income and wealth gains for those at the very top and stagnant living standards for the majority. I think it is appropriate to ask whether this trend is compatible with values rooted in our nation’s history, among them the high value Americans have traditionally placed on equality of opportunity.

No, that wasn’t Elizabeth Warren, or the editor of the Nation, or Paul Krugman (or even me) banging on about how the rich are getting richer and most everybody else is struggling to keep up. It was Janet Yellen, the chairwoman of the Federal Reserve, addressing a conference in Boston on Friday morning. It’s not unheard of for a Fed chief to discuss rising inequality: Ben Bernanke addressed it in a 2007 speech. But Yellen’s speech is surely the first time a Fed chief has pointed out that rising inequality threatens America’s sense of itself.

Yellen began by noting that inequality is still rising. During the Great Recession, income fell more steeply at the top, largely as a result of the decline in the stock market. That caused inequality to “narrow slightly,” she said, but it “resumed widening in the recovery, and by 2013 it had nearly returned to the pre-recession peak.”

That’s an important finding, because some other studies, including one I wrote about a couple of weeks ago, suggest that, by some measures, income inequality has levelled off during the past decade. Yellen drew on data from the Fed’s own Survey of Consumer Finances, the latest of which was carried out in 2013 and was published last month. (The S.C.F. is a sample-based survey, but the sample is large: about six thousand households.) The income measure she focussed on was the share of over-all income going to the richest five per cent of households.

Turning to wealth, which includes financial assets, real estate, and durable goods, such as cars, Yellen noted that the pattern was the same—except the increase in inequality had been even more stark. In 1989, the richest five per cent owned fifty-four per cent of over-all wealth. By 2010, that figure had risen to sixty-one per cent. And by 2013, it had reached sixty-three per cent.

Since the top five per cent of households own almost two-thirds of the wealth, it stands to reason that most American households don’t own very much at all. But the figures that Yellen presented are still shocking. In 1989, the bottom half of the distribution owned just three per cent of all wealth. By 2013, that figure had fallen to one per cent. No, that’s not a typo: half the country owns one per cent of its wealth.

These numbers confirm an old but rarely stated truth. Many, if not most, individual American households possess next to nothing. In 2013, the average net worth of the sixty-two million households in the bottom half of the distribution was eleven thousand dollars. (To get net worth, you add up the value of all the assets a family owns and subtract its debts, including mortgage debts.)

And it’s not just that most households don’t have much wealth. According to this measure, anyway, they have been getting poorer—a point that is often vigorously contested. In 1989, the average net worth of families in the bottom fifty per cent was twenty-two thousand dollars. Twenty-four years later, the average net worth had fallen by half. (These figures are adjusted for inflation.) At the top of the distribution, of course, history has proceeded along very different lines. In 1989, the average net worth of families in the top five per cent was $3.6 million. By 2013, that figure had risen to $6.8 million.

After presenting this dismal picture, Yellen looked at several “building blocks of opportunity” that might serve to alleviate or reverse rising inequality: early education, higher eduction that families can afford, and the creation of new businesses. But she didn’t have much good news to report in any of these areas, either.

The median wealth of families with children in the bottom half of the distribution was just eight thousand dollars in 2013, the Fed chief said. To educate their children, and give them a chance of moving up, these households are almost entirely dependent on the government. Since 1990, the number of children in preschool has risen quite a bit, Yellen noted, but other countries have done even more: “In 2010, the United States ranked twenty-eighth out of thirty-eight advanced countries in the share of four-year-olds enrolled in public or private early-childhood education.”

Confirming what we know from other sources, Yellen said that the Survey of Consumer Finances “shows that most students and their families are having a harder time affording college.” In the past decade, outstanding student debt has quadrupled, to $1.1 trillion. And the burden has been concentrated on low- and middle-income families. For households in the bottom fifty per cent, outstanding education debt rose from twenty-four per cent of average yearly income in 2004 to fifty-eight per cent in 2013. “The education-debt burden was lower and grew a little less rapidly for the next forty-five per cent of families, and was much lower and grew not at all for the top five per cent,” Yellen said.

With a good deal of justification, the United States has always viewed itself as an entrepreneurial country. Although most new businesses fail, founding a new company is still a key way for people to move up the income distribution, Yellen said. “However, it appears that it has become harder to start and build businesses,” she added. “The pace of new business creation has gradually declined over the past couple of decades.” This decline could serve to depress the growth of productivity, wages, and employment, Yellen went on, and it “may well threaten what I believe likely has been a significant source of economic opportunity for many families below the very top in income and wealth.”

It was hardly an uplifting speech. It was an important one, though, and Yellen was perfectly justified in giving it. The Fed’s legal mandate is to stabilize prices and promote maximum employment growth. But it has always been concerned with broader issues as well, such as maintaining financial stability and promoting long-term prosperity growth. Rising inequality impinges all of these things, and it can’t be ignored—least of all by the top economic official in the country.

Correction: This post has been updated to acknowledge that Ben Bernanke addressed inequality in a 2007 speech.