NEW YORK—Rubin Schron, president of Cammeby’s International, has offered $2 billion in cash to buy the Empire State Building, according to a letter an attorney for the investor sent on Tuesday to an attorney for Malkin Holdings, the firm that controls the iconic skyscraper.

Schron proposed to make a $50 million non-refundable deposit once the contract was signed, and close within 90 days, the letter, written by Stephen Meister, a partner at the law firm Meister, Seelig and Fein, said.

Schron alternately offered the current owners an option to participate in a new ownership structure for the 102-story tower, located at 350 Fifth Avenue.

The proposal comes almost a month after the required 80 percent of the building’s investors signed on to approve the creation of a publicly traded real estate investment trust, Empire State Realty Trust, composed of the tower and 20 other buildings.

However, according to some published reports, the skyscraper may be worth more—$2.5 billion.

“There is, of course, no guaranty of the price at which Empire State Realty Trust Inc. securities will trade once the lock-out period expires,” Meister wrote in the letter. “For that reason, we trust that Malkin Holdings, consistent with its fiduciary duties, will give serious consideration to this offer.”

Meister represents investors who have been battling the initial public offering for months, and as of May had six clients who objected to a $55 million settlement that resolved a series of lawsuits from shareholders who had opposed the REIT’s formation.