Japan's biggest bank has been accused by New York officials of dodging tough oversight by swapping its state license for a federal one, putting itself under a U.S. agency on the front lines of President Donald Trump's push to ease financial rules.

The November move by Mitsubishi UFJ Financial Group Inc. is now drawing scrutiny from a key U.S. Senate investigative panel known for its post-crisis probes into Goldman Sachs Group Inc. and other financial firms, said a person with knowledge of the matter.

The Senate's Permanent Subcommittee on Investigations has been gathering documents about how MUFG dropped its New York license and won approval to instead be supervised by the Office of the Comptroller of the Currency, said the person who asked not to be named because the review isn't public.