WASHINGTON (Reuters) - A senior U.S. tax policy aide is resigning from the Trump administration to become a bank lobbyist, the White House confirmed late on Monday, less than six months after Republicans approved deep tax cuts for businesses.

Shahira Knight will become executive vice president of the Clearing House Association as it merges with the Financial Services Roundtable. The combined group will advocate for the interests of large banks, it said in a statement.

The statement quoted Knight as saying she was “excited for the opportunity to help launch a new organization that will advance thoughtful policies for an industry so critical to the growth of our economy.”

Knight, formerly a vice president for financial group Fidelity Investments and a senior aide for the tax-writing House of Representatives tax committee, joined the White House in January 2017 as part of the National Economic Council (NEC).

“Shahira has been a valued leader and member of the NEC team. Not only did she play a central role in developing and enacting historic tax reform last year, but she also helped coordinate and drive the president’s economic growth agenda,” Larry Kudlow, NEC director since mid-March, said in a statement.

Knight did not immediately respond to a request for comment.