The disclosure is a setback for the company and for Edward S. Lampert, the hedge fund manager who engineered the combination of the two legends of American retail 13 years ago. Mr. Lampert has shut down stores, reshuffled the company’s organization and pushed to have a greater online presence. Still, Sears Holdings has lost more than $5 billion over the last three years as sales have declined.

On Wednesday morning, in the first day of trading after the disclosure, shares in the company tumbled more than 13 percent.

Sears, through its catalog, has been a fixture of American homes for more than a century. Kmart, which has its own lengthy history beginning as a five-and-dime store in Detroit, became a major national presence in the 1960s as a big-box department store, with Blue Light Special discounts geared toward penny-wise middle-class Americans.