Icahn, who owns around 23 million shares in Occidental valued at around $900 million, was intensely critical of the group's recent $38 billion takeover of Anadarko Petroleum ( APC ) a deal he called "one of the worst I've ever seen", and one that has cost Occidental more than $21 billion in market value. The new stake is around 10 million less, in share terms, than his earlier holdings, which peaked at around $1.6 billion in late May. "In our view, the OXY/Anadarko merger made no sense for stockholders, but perhaps it made sense for Vicki Hollub, OXY's President and CEO, and certain Board members who, we believe, were concerned that OXY would be a takeover target, and therefore grossly overpaid to acquire Anadarko in order to protect themselves and their jobs," Icahn wrote in an open letter to shareholders. "The Company's actions are especially reprehensible since management repeatedly pledged that it would not engage in risky M&A and would maintain a prudent balance sheet ," he added.