Exterior of J.C. Penney store.

Shares of J.C. Penney Co. Inc. on Friday continued their downward slide as investors digested the latest battle between William Ackman of Pershing Square Capital Management, the retailer’s largest shareholder, and his call for the ouster of retailer’s chairman.

In Friday’s missive to Penney’s board, Ackman wrote: “The board must be led by a chairman who is unbiased, can make decisions without regard to personal relationships, and focused only on what is best for the corporation.

“In recent weeks, our board has ceased to function effectively,” he wrote.

He detailed some of the steps that interim chief executive officer Myron “Mike” Ullman 3rd has taken since replacing former ceo Ron Johnson, and even noted that he didn’t know of Debra Berman’s hiring as the new marketing chief.

“Imagine my surprise when I learned of Ms. Berman’s hiring from a press release on my Bloomberg machine,” Ackman wrote.

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He also wrote about his concern of the retailer’s budgeting process.

Ackman stated: “We received three different financial projections — a new one at each of the last three board meetings — each one projecting worse results than the previous one. Most disconcerting was Mike’s disavowal of the first two projections when he explained at the last meeting that those were not ‘his numbers.’ I find this particularly troubling because these projections were presented by Mike himself to the board in May and in June so it is hard for me to understand why he should not have ownership for May and June’s projections.”

In seeking the ouster of chairman Thomas Engibous, Ackman wrote: “I have lost confidence in our chairman’s ability to oversee this board. I would therefore recommend that Tom be replaced as our chairman.”

Shares of the retailer began its slide on Thursday after Ackman sent a letter to the board seeking acceleration of the ceo search process, and pushing for former ceo Allen Questrom to return as the company’s chairman.

The stock continued sliding on Friday, trading down 4.1 to $13.09 in early morning trading. It then seesawed back and forth in a trading range of between being down 2.9 percent to being down 3.7 percent in mid-morning trading.

When news surfaced on CNBC that Ackman sent another letter to fellow Penney’s board members, the stock slid down 5.4 percent to $12.92.

Penney’s board late Thursday, through Engibous, fired back crediting Ullman with helping to improve the company’s financial position since taking over in April.