Billionaire media mogul says in letter that proposal to reunite companies he split up a decade ago is ‘Not optimal’ for shareholders.

Murdoch sent a letter to News Corp and Fox withdrawing his proposal to reunite the companies, according to a regulatory filing. He indicated that he and his son, Fox Corp chief executive Lachlan Murdoch, had determined that the combination is “not optimal” for shareholders.

Prominent News Corp investors had been critical of the proposal.

Special committees of the Fox and News Corp boards that were reviewing the proposed merger have now been dissolved, the companies said in statements.

The planned merger would have combined the right wing and highly controversial TV channel Fox News and TMZ assets with News Corp’s news operations, which include the Times and the Sun newspapers and websites in the UK, the Wall Street Journal and New York Post in the US, and the Australian.

Murdoch had originally divided his media empire in 2013, placing the print business in a new public entity, News Corp, and the TV and entertainment under 21st Century Fox. The merger would have effectively reunited them.