Mr. Clayton, who says he will recuse himself from certain cases involving former clients, has also personally invested in a number of hedge funds and private equity firms through special Sullivan & Cromwell investment vehicles, according to the filing. He earned $7.6 million from Sullivan & Cromwell over the past year or so and has investments in portfolios managed by Apollo Global Management, Bain Capital, J.C. Flowers and Perry Partners. His wife, Gretchen, who works at Goldman Sachs, has a number of investments in Goldman-managed funds as well as a small amount, described in his filing as being less than $1,001, with a retirement account once managed by Omega Advisors, a hedge fund now fighting S.E.C. charges.

Mr. Clayton’s disclosures offer a rare glimpse into his client list and family wealth — a sum of at least $50 million, his filing shows — and may reinforce a view among consumer groups and Democratic lawmakers that he could have conflicting interests as a Wall Street regulator. Although he is expected to broadly support the agency’s enforcement efforts, he has made statements suggesting that he will probably move to ease at least some of the Obama-era regulations weighing on Wall Street clients.

Some of those clients are well represented in the new administration, perhaps none more than Goldman. The Trump administration has become a virtual magnet for former Goldman executives: Steven Mnuchin, the Treasury secretary; Gary D. Cohn, the chairman of the national economic council, and Stephen K. Bannon, Mr. Trump’s chief strategist, have all worked at Goldman.

The addition of Mr. Clayton, who represented Goldman during the 2008 financial crisis, will most likely fuel concerns that the bank has outsize influence in the administration.

But one Democrat is scrutinizing more than just Mr. Clayton’s ties to Wall Street. In a previously unreported letter, Senator Catherine Cortez Masto, Democrat of Nevada and one of the newest members of the Senate Banking Committee, questioned him on his representation of the Nordic telecommunications company TeliaSonera.