Global regulators on Thursday said Citigroup Inc , Deutsche Bank , HSBC and JPMorgan Chase & Co will need to hold the most extra capital of 28 banks considered so large and complex they need an extra buffer to absorb potential losses.

The additional cushion aims to make sure large banks won't threaten the financial system in future crises and require government bailouts.

Thursday's statement was timed for a meeting of G20 finance ministers in Mexico this weekend when governments will review progress in implementing a welter of pledges to reform finance after the 2007-09 crisis.

(Reporting by Rick Rothacker in Charlotte, N.C.; Editing by Gary Hill)