U.S. Senator Elizabeth Warren scored a coup in her campaign to improve oversight of the beleaguered bank Wells Fargo & Co. (WFC - Get Report) , as Federal Reserve Chair Jerome Powell promised to hold a full vote of the regulator's board before lifting sanctions imposed earlier this year.

In a letter Thursday to the Massachusetts Democrat, Powell wrote that a full vote of the Fed board of governors will be held prior to lifting the asset-growth suspension placed on Wells Fargo in February. Previously, the decision on when and whether to lift the sanctions would have been delegated to Wells Fargo's regional overseer, the Federal Reserve Bank of San Francisco, with the concurrence of the national Fed's director of supervision.

"I'm glad the Fed's board of governors changed course and will ?vote on whether to lift the growth restriction, rather than delegating that important question," Warren said in a press release.