Entain has offered to buy Tabcorp Holding’s wagering and media business for $3.5 billion the Australian betting firm said on Tuesday.

The proposal by Entain is subject to due diligence, securing financing and regulatory approvals, Tabcorp said, adding that it was assessing the offer.

“The Tabcorp board has carefully considering the proposals and formed the view that the proposals do not adequately value Tabcorp’s Wagering & Media business,” Tabcorp said.

Investors have grown frustrated with Tabcorp over the performance of the wagering arm, which has been losing ground to online rivals such as Sportsbet and Ladbrokes for over a decade, since its $11 billion merger with Tatts in 2017.