WASHINGTON (Reuters) - Northern Trust Corp (>> Northern Trust Corporation) had shortcomings in its "living will" plans and has until year-end to update a proposal for how to unwind if it went bankrupt, U.S. regulators said on Friday as they granted an extension for four foreign banks to comply.

Barclays Plc (>> Barclays PLC), Credit Suisse Group AG (>> Credit Suisse Group AG), Deutsche Bank AG (>> Deutsche Bank AG) and UBS Group AG (>> UBS Group AG) each received one-year extensions to July 2018 to satisfy regulators on their living wills, according to the U.S. Federal Reserve.

Large foreign banks must operate all their U.S. businesses under one corporate umbrella, the Fed declared in 2014. Friday's extension should give those banks more time to comply.

The Fed and Federal Deposit Insurance Corp on Friday granted the extension and gave guidance to those four banks "to reflect the significant restructuring that they have undertaken to form intermediate holding companies."

A Northern Trust spokesman was not immediately available for comment.

Fifteen of the 16 other domestic financial services companies reviewed under this part of the living will exams passed, the regulators said.

Those domestic companies are American Express Co (>> American Express Company), Ally Financial Inc (>> Ally Financial Inc), BB&T Corp (>> BB&T Corporation), Capital One Financial Corp (>> Capital One Financial Corp.), Comerica Inc (>> Comerica Incorporated), Discover Financial Services (>> Discover Financial Services), Fifth Third Bancorp (>> Fifth Third Bancorp), Huntington Bancshares Inc (>> Huntington Bancshares Incorporated), KeyCorp (>> KeyCorp), M&T Bank Corp (>> M&T Bank Corporation), Regions Financial Corp (>> Regions Financial Corp), SunTrust Banks Inc (>> SunTrust Banks, Inc.), PNC Financial Services Group Inc (>> PNC Financial Services Group Inc), U.S. Bancorp (>> U.S. Bancorp) and Zions Financial Bancorp (>> Zions Bancorp).

(Reporting by Patrick Rucker; Editing by Chizu Nomiyama and Lisa Von Ahn)