Last week, Dow and fellow chemical giant DuPont announced a $130 billion merger that would unite two of America's oldest firms, and see Liveris become executive chairman of the combined entity.
The WSJ reported on Sunday that it had reviewed a private letter Loeb sent to Dow's board, in which he said making Liveris executive chairman was an "insult to Dow shareholders." He has previously criticized Liveris' strategy and spending.
In the letter, the activist also questioned whether the huge deal was rushed to completion to prevent him from speaking about it. Until the weekend, Loeb, a longtime and vocal critic of Dow, had been under a so-called standstill agreement with the company that barred him from talking Dow.
Loeb's hedge fund Third Point, with about $17 billion in assets under management, has a 2 percent stake in Dow, making it one of the company's biggest investors.
Loeb is well known for his public brawls with corporate heavyweights including Sony, Baxter International and Yahoo .
Read the full WSJ article here.