Is income inequality holding back the United States economy? A new report argues that it is, that an unequal distribution in incomes is making it harder for the nation to recover from the recession and achieve the kind of growth that was commonplace in decades past.

The report is interesting not because it offers some novel analytical approach or crunches previously unknown data. Rather, it has to do with who produced it, which says a lot about how the discussion over inequality is evolving.

Economists at Standard & Poor’s Ratings Services are the authors of the straightforwardly titled “How Increasing Inequality is Dampening U.S. Economic Growth, and Possible Ways to Change the Tide.” The fact that S.&P., an apolitical organization that aims to produce reliable research for bond investors and others, is raising alarms about the risks that emerge from income inequality is a small but important sign of how a debate that has been largely confined to the academic world and left-of-center political circles is becoming more mainstream.

“Our review of the data, as well as a wealth of research on this matter, leads us to conclude that the current level of income inequality in the U.S. is dampening G.D.P. growth,” the S.&P. researchers write, “at a time when the world’s biggest economy is struggling to recover from the Great Recession and the government is in need of funds to support an aging population.”