Concerned that a merger would undervalue News Corp, investors are asking a special committee of independent board members to look more skeptically at the proposal.

An activist investor escalated its pressure on News Corp on Sunday, asking it to reconsider a proposal by Rupert Murdoch to combine the two parts of his media business, News Corp and Fox.

The investor, Irenic Capital Management, said in a letter to News Corp, which was viewed by The New York Times, that it might vote to oppose the merger, arguing that the proposed deal is likely to undervalue News Corp.

“We want to be clear: Walking away from a potential transaction is better than agreeing to a deal that fails to maximize News Corp’s value,” Irenic said in the letter, which was addressed to the special committee of independent board members evaluating the merger proposal.

Irenic owns about 2 percent of News Corp’s class B shares, according to the letter. Those shares confer stronger voting rights than the more numerous Class A shares.

Along with the letter, Irenic sent an email asking to meet with the special committee to share its views and those of other shareholders.

It’s the second time Irenic has requested a meeting. Last month, Irenic did so as it urged News Corp to explore splitting its online real estate listings unit from its other businesses, including The Wall Street Journal, HarperCollins and The New York Post. The firm is being advised by executives including Jon Miller, a former chief digital officer of News Corp.