Earlier this week, Malkin Holdings said in a letter to investors that it was reviewing two unsolicited bids—one for $2.1 billion and the other for $2 billion—to buy the 102-story building. The letter was included in a filing with the U.S. Securities and Exchange Commission.
Malkin Holdings had said it would consider the two previously unsolicited offers, consistent with its fiduciary duties.
In addition to its presence in New York, Thor Equities owns and develops urban real estate throughout the United States, Latin America and Europe.
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Meister Seelig & Fein, the law firm representing investors who oppose the REIT plan, disclosed a letter last week from privately held Cammeby's International Group offering to buy the building for $2 billion.
The second bidder's identity was not disclosed in the most recent SEC filing.
Malkin Holdings led the plan to put the Empire State Building and more than 17 other properties into a real estate investment trust called Empire State Realty Trust Inc, which would be publicly traded under the proposed symbol "ESB" on the New York Stock Exchange. Investors recently approved the REIT plan.
Malkin Holdings, the Helmsley Trust and investors would have to approve a sale. The Helmsley Trust is the majority owner of the company that owns the building's sublease, which expires in 2076.
An appraisal conducted last summer valued the Empire State Building at about $2.33 billion, after debt, according to the SEC filing. Including the mortgage, the historic skyscraper is valued at about $2.53 billion, that appraisal showed.