RPT-INSIGHT-US banks' buybacks, dividends may be no reason for shareholder celebrations

NEW YORK, March 11 (Reuters) - Big U.S. banks, including JPMorgan Chase & Co and Citigroup Inc, are expected to win Federal Reserve backing on Wednesday to buy back more shares and increase their dividends in the coming year, but the approvals may be as much about the institutions' financial engineering as any improvement in their health.