Federal Reserve chair Janet Yellen donned something of a critical theorist’s cap on Wednesday, citing research that laments financialization and the subsequent “’rent seeking’ activity that may promote inefficiency” it allegedly caused.

“Recent research has raised important questions about the benefits and costs of the rapid growth of the financial services industry in the United States over the past 40 years,” Yellen noted at a gathering sponsored by the Institute for New Economic Thinking in Washington.

According to her prepared remarks, on “Finance and Society,” Yellen based the claim on studies that explore “distortions in the financial sector” and rent-seeking (when market actors leverage monopoly power to extract money from consumers), the relationship between bankers’ salaries and the increase in income inequality, and “links between financial development and economic growth, focusing particularly on these relationships around periods of rapid growth in the financial sector.”

Yellen also noted a 2007 study that shows financial sector development does alleviate inequality and poverty, but only “up to a point.”

Drawing heavily throughout her speech on lessons learned from the 2008 financial crisis, the central banker warned that banks’ dominance over other productive sectors is something to seriously lament, noting at the onset of her remarks that “when the incentives facing financial firms are distorted, these firms may act in ways that can harm society.”

“Financialization” refers to the massive relative growth of the financial sector—the banking, insurance, and real estate industries—over the past four decades compared to the overall economy. Between 1970 and 2010, the financial sector’s share of gross domestic product increased to roughly 21 percent from 15 percent.

Left-leaning professor of economics Michael Hudson, in 2003, said that the term “financialization” could “almost” be likened to “a lapse back into the pre-industrial usury and rent economy of European feudalism.”