Canadian pop star Avril Lavigne is splitting ties with Nettwerk management, sources at the company confirm to Billboard.biz. Her departure was announced internally last week. Vancouver-based Nettwerk CEO Terry McBride did not immediately return calls to Billboard.biz about the split, and a publicist for Nettwerk would not comment on the matter. McBride and Nettwerk manage other acts, including the Barenaked Ladies and Stereophonics. Lavigne's most recent RCA release, "Best Damn Thing," has sold 1.5 million copies in the United States, according to Nielsen Soundscan. Lavigne first came to the attention of McBride after the artist sent a VHS tape, which featured her singing karaoke in the basement of her parents' house. McBride did not have a management deal with Lavigne at the time, and Nettwerk let her out of a development deal to allow her to sign with SonyBMG. However, prior to the 2002 release of her debut, "Let Go," Lavigne parted ways with her management and signed a deal with McBride and Nettwerk. McBride managed Lavigne through a tumultuous time in the music industry, including a lawsuit by songwriters James Gangwer and Tommy Dunbar, who claimed that the artist's track "Girlfriend" plagiarized their "I Wanna Be Your Boyfriend." The case was later settled. McBride also pushed Lavigne into new areas, utilizing technology through arrangements with the likes of youtube.com and promoting her into Asian markets. McBride, who is often outspoken about issues facing the music industry, would later use his work with Lavigne to demonstrate new initiatives Nettwerk was undertaking in artist branding and through the Internet.