Rising U.S. income inequality has more to do with technological change and globalization than tax policy, Federal Reserve Chairman Ben Bernanke said on Wednesday.

Tax policy is not the major factor, Bernanke said in response to a question from the House Financial Services Committee after presenting his twice-yearly testimony on the U.S. economy.

The major factors are technological change ... and to a lesser extent, globalization, he said.

Bernanke acknowledge that middle-class income growth was not keeping up with the higher income brackets, but inequality of wealth holdings was worse than inequality of income.