As chief of global fixed income at BlackRock, Keith Anderson has just the sort of spacious, elegantly understated office you might expect from a modern Master of the Universe. But step into his home study and you can begin to see the hipster within; the walls are lined with gold and platinum records.

Anderson, 47, is the sole investor with a stake in both Octone and Downtown Records, two independent labels backed by Wall Street money. “They’re the only investments I’ve ever made that my kids think are cool,” he says.

A lifelong music lover, Anderson was among the first people approached by his boss, BlackRock C.E.O. Laurence Fink, to join Octone in 2000. He got involved with Downtown in late 2005 through co-founder Terence Lam, a VH1 veteran—and the father of one of his children’s classmates—who started the label with Allen & Co. banker John Josephson and music exec Josh Deutsch. Anderson, jazzed by Octone’s success, signed on for an amount he declines to specify. Downtown has about a dozen investors with stakes of varying sizes and was launched with what Deutsch characterizes as “considerably less” than Octone’s $5 million in seed money.

Soon after, Anderson tried to get Fink and other Octone partners to invest in Downtown, but they thought one long-shot record company investment was enough. Still, several of Octone’s backers met with Josephson, Deutsch, and Lam, who became Downtown’s general manager, to offer advice about setting up the label.

Less than six months later, Downtown released Gnarls Barkley’s St. Elsewhere, which has sold more than a million copies. The label has also signed indie rockers Cold War Kids as well as the Eagles of Death Metal and Art Brut, both of which will release new albums this summer. And Anderson has become known in his circle—and to his kids—as the hippest square guy in town.