Reuters could not immediately reach Macy's and Starboard Value for comment outside regular business hours.
Starboard owns a 1.04 percent stake in Macy's, according to Thomson Reuters data.
In an email reply to the Journal, Macy's said it is reviewing Starboard's letter and views expressed by the investment firm are consistent with actions already underway at the company, the paper said.
Last week, Macy's reported disappointing results and said it will eliminate more than 2,000 jobs which will help it save $400 million.
Earlier last year, Starboard bought a stake in the company and said the U.S. retail chain's stock was trading at more than 70 percent below value, and that its highly-prized real estate assets could be spun off.
By Starboard's estimate, the Herald Square store alone was worth $4 billion, while properties in San Francisco and Chicago were worth more than $1 billion. With another 400 mall locations worth about $13 billion, Macy's had a real-estate value of about $21 billion, Chief Executive Jeffrey Smith said at a conference last year.