Lloyd Blankfein, the former head of Goldman Sachs, mocked Sen. Elizabeth Warren on Thursday after she featured him in an advertisement attacking billionaires for greed.

Blankfein ran Goldman from 2006 until retiring at the end of 2018. He is now senior chairman of the firm.

Blankfein was one of the billionaires featured in her latest political ad, which aired on CNBC on Thursday. The ad calls for a wealth tax and features clips of billionaires criticizing Warren. It arose after Warren’s dispute with Wall Street billionaire Leon Cooperman.

Blankfein traded jabs with Senator Bernie Sanders, a rival of Warren’s for the Democratic presidential nomination, in July.