The activist investor at Supervalu is recommending even more radical changes than it previously did, saying now that the company should be broken up.

Blackwells Capital LLC in New York, which owns 4.35 percent of Supervalu’s stock, sent a letter to the Supervalu board Tuesday recommending a separation of the company’s wholesale and retail divisions. The wholesale business, which provides about three-fourths of revenue and nearly all its operating profit, should be shopped to potential buyers, such as SpartanNashCo or United Natural Foods, Blackwells said.

The company responded in a statement that said it has already “taken a number of critical steps to transform” the wholesale business, including the recent acquisitions of Unified Grocers and Associated Grocers, and unlock its value for shareholders.

Supervalu also sold its biggest retail operation, the Save-A-Lot chain that operated in the central U.S., in 2016 in part to put more emphasis on the wholesale business.

The Eden Prairie-based company said it “continues to pursue options for certain retail banners and its real estate portfolio, while remaining focused on reducing costs.” The company’s retail banners include Cub Foods, a Minnesota-focused chain that is the largest grocery in the Twin Cities, Farm Fresh, Hornbacher’s, Shop n Save and Shoppers.

In October, Blackwells urged Supervalu to sell one-third of its grocery stores, parts of its real estate and bring new leadership. Blackwells wants to nominate several directors of its own and try to get shareholder support.

Shares of Supervalu have been sliding for several years. The stock was down more than 30 percent before news of Blackwells’ latest letter. This morning, Supervalu shares are up about 5 percent.