The Rupert Murdoch empire has formed a joint venture with VeriSign, which bought Jamba for $270m in 2004.
The company, which operates as Jamster in countries including the UK, is best known for bringing the Crazy Frog and Sweety the Chick characters to handsets and television advertisements.
"The joint venture combines Jamba and Fox Mobile Entertainment assets to form a leading global provider of mobile entertainment," News Corp said in a statement.
"Lucy Hood, who was formerly president of Fox Mobile Entertainment, will become the company's CEO effective immediately upon the close of the deal."
In September, News Corp announced it would pay $188m for a 51% stake in the company. But Jamba has previously faced criticism for locking customers in to unexpected mobile sales and for covering youth TV channels with repeat commercials.