One source told Fox that a formal announcement of Mnuchin's nomination could come as early as Wednesday.
Mnuchin had long been considered a favorite for the Treasury position. Two weeks ago, businessman and close Trump associate Carl Icahn (JEW) tweeted that Trump was considering Mnuchin for the post.
Mnuchin, 53, was appointed Trump's campaign finance chair this past May. Through his work, Mnuchin grew close to Trump's children and son-in-law, Jared Kushner (JEW) -- a top adviser to Trump -- and worked with them on fundraising events.
The campaign raised at least $169 million, in addition to the $66 million Trump spent out of his own pocket. Though that was far short of what Hillary Clinton raised, it represented an impressive haul given that Trump didn't begin fundraising in earnest until the end of May.
If approved by the Senate, Mnuchin would follow in the tradition of two previous treasury secretaries -- Robert Rubin (JEW) in the Clinton administration and Henry Paulson (JEW)in George W. Bush's. All had vast Wall Street experience gained from years spent working at Goldman Sachs.
Yet unlike Rubin (JEW) and Paulson (JEW)and unlike President Barack Obama's two treasury secretaries, Timothy Geithner (JEW) and Jacob Lew (JEW), Mnuchin would bring no government experience to Treasury, something that could prove a hurdle in navigating the tricky politics of Washington.
After graduating from Yale in 1985. Mnuchin worked for Goldman Sachs for 17 years. His father, Robert Mnuchin (JEW), had himself worked for Goldman for three decades, becoming a partner in charge of equity trading.
The younger Mnuchin amassed his own fortune at the firm and then left in 2002. He worked briefly for Soros (JEW) Fund Management, a hedge fund led by George Soros(JEW), before starting his own investment firm, Dune Capital Management.
As head of this firm, Mnuchin and other investors participated in the purchase of failed mortgage lender IndyMac in 2009 and renamed it OneWest. The failure of IndyMac in 2008 with $32 billion in assets was one of the biggest casualties of the housing bust.
Mnuchin became chairman of OneWest, which was sold to CIT Group in 2015. Before the sale, OneWest faced a string of lawsuits over its home foreclosure practices.
This month, housing advocates filed a complaint asking the Department of Housing and Urban Development to investigate OneWest for possible violations of the Fair Housing Act. The lender failed to place branches in minority communities, provided few mortgages to black homebuyers and preserved foreclosed properties in white neighborhoods while allowing similar homes in minority communities to fall into disrepair, according to the California Reinvestment Coalition and Fair Housing Advocates of Northern California.
CIT declined to respond directly to the complaint but stressed in a statement that it is "committed to fair lending and works hard to meet the credit needs of all communities and neighborhoods we serve."
Mnuchin also became a major investor in Hollywood, helping finance a number of movies, including the 2009 blockbuster "Avatar."
As treasury secretary, Mnuchin would be the administration's chief economic spokesman, serving as a liaison not only to Wall Street but also to global investors, a critical role given the trillions of dollars in treasury bonds owned by foreigners. In addition, it would be his job to sell the new administration's economic program to Congress.
Mnuchin will also oversee a sprawling bureaucracy that includes the Internal Revenue Service and the agency that issues millions of Social Security and other benefit checks each month. Treasury also runs the agency that wages the financial war on terrorism.