It is the second time the Swedish Tax Authority has claimed the 61-year-old singer dodged taxes by not declaring millions in royalties going back decades, officials said Thursday.
Victor Palm, a tax official, said the former star was "paying less tax" than he should, adding that the authorities suspect royalty payments to Ulvaeus were made to companies operating in foreign tax havens.
Ulvaeus' financial adviser wasn't immediately available for comment.
Last year, the authority claimed almost $13 million in back taxes, fees and interest on unpaid taxes related to contracts he signed before moving to England in 1984.
Officials claimed the contracts, which handed over the rights to Ulvaeus' royalties from ABBA songs and the musical "Chess" to various companies, were sham and that he still had access to the money.
The tax office agreed to reduce its claim to around $9.5 million, but Ulvaeus appealed the case. It wasn't clear when the court would consider the appeal.
Ulvaeus was a co-founder of ABBA in 1966 with Benny Anderson. The four-member group, which also included Agnetha Faltskog and Anni-Frid Lyngstad, had a string of hits including "Dancing Queen," "Mamma Mia" and "Take a Chance on Me." The group, which last performed together in 1982, sold more than 370 million albums worldwide.