NEW YORK (AP) — Activist investor Starboard Value wants Macy's to tap the value of its real estate assets by splitting them off into separate companies.

Starboard's plan published Monday urges the department store operator to create two joint ventures. One would hold its properties in New York, San Francisco and other major cities, while the other would hold its mall properties. Altogether, Starboard said the department store's real estate is worth about $21 billion.

Creating the joint ventures with real estate partners could boost the value of Macy's stock to $70, Starboard said, nearly double what it's currently worth. Starboard has a 1 percent stake in Macy's, according to FactSet.

Macy's said it received the plan from Starboard and is reviewing it. Last year, Macy's said it was exploring joint ventures to redevelop some of its properties, including the ones in New York and San Francisco.

"The viewpoint expressed by Starboard is consistent with actions already under way at Macy's," the company said in a statement.

Shares of Macy's rose $2.35, or 6.5 percent, to $38.24 in afternoon trading Monday.

The plan from Starboard comes after Macy's had a rough holiday season.

Last week, the company reported that sales at existing stores and excluding licensed departments fell 5.2 percent in November and December. Macy's said it would cut 4,800 jobs from its total of 163,000 workers.

Macy's Inc., which has corporate offices in Cincinnati and New York, operates about 900 stores, including Bloomingdale's and Bluemercury.