STAMFORD, CT—Land and Buildings, among the most activist investors in the real estate sector, has nominated four directors to the board of shopping center REIT the Macerich Co., an industry source familiar with the matter confirms. Bloomberg Business and the Wall Street Journal have both reported that Land and Buildings submitted the nominations ahead of a deadline Tuesday, prompted mainly by objections to measures that MAC took to defend itself against an ultimately unsuccessful $22.4-billion hostile takeover by Simon Property Group.

However, Land and Buildings founder Jonathan Litt told Bloomberg that MAC was challenging the validity of his nominations, who were not identified. Among other matters, there's the question of whether Land & Buildings owned shares in time to submit nominees.

Land and Buildings currently holds about 1,000 shares of MAC stock, the WSJ reported Thursday. That's a small share by activist investor standards, but is enough to submit board nominations. However, it's not clear whether Litt will be in a position to pursue a proxy battle during the REIT's annual meeting later this spring.

The WSJ reported that Litt has emerged as the most prominent activist investor in the REIT space. He has pushed for shakeups at Pennsylvania Real Estate Investment Trust and BRE Properties, and last year won a seat on the board of Mack-Cali Realty Corp.

His push for change at MAC comes on the heels of two other proxy battles that Land and Buildings is pursuing. Earlier this week, Litt filed a preliminary proxy statement for the annual meeting of MGM Resorts International Ltd., which he believes should pursue a REIT conversion. Last month he nominated four directors to MGM's board, including himself.

In March, Litt continued his push for change at apartment REIT Associated Estates Realty Corp., saying that he intended to nominate himself and two others to the company's board. Among the other nominees is R. Scot Sellers, formerly CEO of Archstone-Smith Trust.