Hit songwriter Kara DioGuardi is putting her copyright interests up for sale, Billboard.biz has learned. On the auction block are all of her rights, including her writer's share, in songs she's written and co-written through June 30 of this year, sources say.

A search of The Billboard Hot 100 and Hot R&B/Hip-Hop Songs shows that DioGuardi has co-written 20 charting songs in the last five years.

Of these, Christina Aguilera's "Ain't No Other Man" was certified platinum. Five other recordings were certified gold: Hilary Duff's "Come Clean"; Ashlee Simpson's "Pieces of Me" and "La La"; Gwen Stefani's "Rich Girl" featuring Eve, which is the only R&B charting song; and Kelly Clarkson's "Walk Away." DioGuardi also co-produced Clarkson's hit.

Licensing rights in most of the songs are not exclusively controlled by DioGuardi.

Sources say that Stephen Finfer with ArtHouse Entertainment is handling the