NEW YORK (CNNMoney) -- Jay Clayton, a star Wall Street lawyer picked to lead the SEC, has a list of clients that reads like a who's who of companies accused of shady practices.

There's Volkswagen, which has pled guilty to criminal charges over cheating on emissions tests; Valeant, a drug maker accused of being the "Enron" of the pharma world for fraud; and Deutsche Bank, which has been charged in a $10 billion Russian money-laundering scheme;

Clayton, who will be quizzed about his ties to troubled companies during his confirmation hearing on Thursday, also represented the very industry he is supposed to police -- he advised Goldman Sachs on its controversial government bailout and Bear Stearns in its 2008 fire sale to JPMorgan.

As a partner at the elite law firm Sullivan & Cromwell, Clayton pulled in $7.6 million in the last year and could make another $1 million when he steps down, according to recently-filed financial disclosure forms.

Democrats are already attacking Clayton's extensive ties to the financial industry. They question how he'll be able to keep Trump's promise not to let Wall Street "get away with murder" by now watching over the very companies he was paid to defend.

Senators Bernie Sanders and Jeff Merkley are expected to appear at a rally in Washington, D.C. on Wednesday to urge their colleagues to reject Clayton's nomination. Activists have pointed to Clayton's "massive conflicts of interest and cozy relationship with Wall Street."

Clayton would help Trump deregulate

If confirmed, Clayton would oversee an agency charged with protecting investors, rooting out financial crime and ensuring capital markets are fair to all.

Clayton would also play a key role in Trump's efforts to rip up what he sees as burdensome regulation from the Obama era. For instance, investors are hoping Clayton's confirmation hearing will make it easier for companies to raise money, in part by relaxing reporting requirements and other rules.

The White House didn't respond to a request for comment for this story, but Trump has previously praised Clayton's background as a Wall Street lawyer. When he nominated Clayton, Trump predicted he will help unleash the "job-creating power" of the economy.

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