WASHINGTON (Reuters) - Leading U.S. banks may find that a Republican plan to ease restrictions on Wall Street is not worth the additional cost of capital, a report from Fitch Ratings said on Wednesday. Representative Jeb Hensarling, chairman of the House Financial Services Committee, authored a banking reform package last year that would allow large banks to drop some regulations if they boost their capital reserves. Under the proposed CHOICE Act, banks would be exempted from safety and soundness rules that limit payouts to investors if the bank maintains a leverage ratio of 10 percent or higher, Fitch said. Banks use retained earnings and stock to shield themselves from market shocks and regulators have asked banks to hold more such capital since the 2008 global financial crisis. But banks have resisted capital standards being set too high, arguing that it hurts investors. Fitch said the largest U.S. banks would need to raise approximately $400 billion of capital to qualify for exemption under the CHOICE Act, an increase of around 43 percent from existing capital levels. (Reporting By Patrick Rucker; Editing by Meredith Mazzilli)