Geithner, 54, secured a credit line with JPMorgan, one of the largest banks he oversaw during the financial crisis, to finance personal investments in funds started by his current employer, Warburg Pincus, according to a filing with the New York Department of State. He is borrowing money to invest in a $12 billion private equity fund that the firm raised in November, its first main fund since he joined almost two years ago, a person familiar with the situation said.

Top private-equity managers are often expected to pony up many millions of dollars for their new funds, to show investors that their interests are aligned.Having worked for the government for most of his career, including as president of the Federal Reserve Bank of New York, Geithner entered that high-stakes world with the earnings history of a government employee, albeita high ranking one. By borrowing money, investors can also amplify -- or leverage -- the returns on their own capital. […]