J.C. Penney Co., the department-store chain that last month posted the lowest annual sales in more than two decades, said speculation that Chief Executive Officer Ron Johnson plans to leave the company is wrong.

“Ron Johnson is not quitting or resigning from J.C. Penney and he has no plans to do so,” Joey Thomas, a spokesman for the Plano, Texas-based company, said today in an e-mail. “The rumors are false.”

Johnson has come under fire after J.C. Penney’s annual revenue slid 25 percent to $13 billion, the lowest since at least 1987, during the first year of his transformation plan. Former CEO Allen Questrom, who retired from the retailer in 2004, said that a turnaround won’t work under Johnson and that the longer the board waits to fire him, “the worse it’s going to get.”

Customers have been increasingly alienated by marketing missteps, a failed attempt to transition away from sales and coupons and Johnson’s plan to turn most stores into collections of boutiques.

Johnson, Apple Inc.’s retail chief before joining J.C. Penney, is now reviving promotions and introducing new brands, including Canadian retailer Joe Fresh, in an effort to rekindle growth.

J.C. Penney pared its gain for the day, rising 1.9 percent to $15.33 at 10:37 a.m. after earlier climbing as much as 4.3 percent. The shares slid 24 percent this year through yesterday after a 44 percent drop in 2012.