According to Ackman's missive, former CEO Allen Questrom has conditionally agreed to return as the company's chairman.
In an interview with CNBC, however, Questrom said that he would only consider a return to the embattled retailer under the right conditions — adding that he would not come back under hostile circumstances. The search for a new CEO should not take more than 30 to 45 days, as there are probably not more than five people who'd be qualified for the job, Questrom said. He also said he was strongly in favor of CEO Ullman at the time he was re-hired in April.
The company has "such a great history, you wouldn't want to give up until it's dead," Questrom told CNBC.
Meanwhile, Wall Street has increasingly soured on the beleaguered retailer. Macquarie retail analyst Liz Dunn said Penney was in dire need of "a big turnaround" after a series of failed attempts to lure back wayward customers. Dunn added that the company was running out of time to get it right.
The company's stock, traded on the New York Stock Exchange, jumped as much as 8 percent on the news, although it is still down more than 36 percent since the start of the year.
JC Penney tells CNBC that any speculation that CFO Ken Hannah is stepping down is completely false, reports CNBC's Courtney Reagan.
The following is the full text of the letter:
To My Fellow Directors:
I am very concerned about the future of J.C. Penney. While I supported the decision to bring back Mike as an interim CEO, it was based on Tom's statement that we would immediately launch a search process for a long-term CEO.