U.S. Securities and Exchange Commission Chair Mary Jo White on Monday defied requests by Senate Republicans to delay adopting new rules until after President-elect Donald Trump takes office, according to a copy of a letter seen by Reuters.

In the letter to the Senate Banking Committee's top two Republicans, Chairman Richard Shelby and Mike Crapo of Idaho, White stressed it was "incumbent" on the independent regulator's canons of ethics to proceed finalizing rules.

Those canons direct the SEC to "exhibit a spirit of firm independence" in performing its regulatory duties "without fear or favor."

White's Dec. 12 letter comes in response to a request last month by Shelby and Crapo for the SEC to cease adopting rules until after Trump had a chance to review the SEC's agenda.

New rules, they said, "can be complex" and "create uncertainty for markets."

They also asked White to provide a list of all rules currently awaiting adoption.

White gave the lawmakers a list of regulations that she said are "ready for Commission consideration" before she plans to depart the agency, including a few derivatives rules mandated by the 2010 Dodd-Frank law, as well as a more controversial one that would limit how mutual funds and exchange-traded funds use derivatives to leverage returns.

"I am not insensitive to the issues raised by your letter and have carefully considered what impact, if any, the election should have on the current work of the Commission," White wrote.

She added that she had confirmed that the SEC "historically has proceeded with its work during comparable post-election periods."

This article was provided by Reuters.