Courtney Love has reportedly sold a quarter of her stake in Nirvana's work because she found managing late husband Kurt Cobain's estate "overwhelming".
Courtney Love has promised the deal will not harm Nirvana's image
Rolling Stone magazine said the deal with record industry veteran Larry Mestel was worth more than $50m (£29m).
"The affairs of Nirvana are so massive and so huge, and they've all fallen on my lap," Love was quoted as saying.
She said she needed a partner to bring the seminal group's songs "into the future".
Love inherited 98% of the group's publishing rights when Cobain, the group's frontman, killed himself in 1994.
However, she has reassured fans that although the sale would take Nirvana where they'd "never been before", the way their music was used would remain "tasteful".
She also promised to retain "the spirit" of the group.
Mestel, formerly the general manager of Virgin Records, told the magazine he was buying into the catalogue because Cobain was "one of the most important songwriters of his time".