Offers to buy the Empire State Building are heading sky-high.

The owners of the iconic tower on Monday had no sooner officially turned down several offers for the 102-story Midtown classic when one of the potential buyers upped his offer by 15 percent, to $1.4 billion.

Joe Sitt’s Thor Equities had earlier offered more than $1.2 billion for Empire State Building Associates, the company that owns the land and the building.

The new bid, placed late Monday, was for the land, the building and the master lease of the over 2 million square-foot tower, which is controlled by Malkin Holdings and the Helmsley Estate, which wants to sell its stake.

Malkin previously obtained the votes it needed to roll the property into a multibuilding real estate investment trust that has been opposed by minority holdout partners.

The emailed bid obtained by The Post was placed through Jason Meister at Avison Young and said these partners would be able to keep their shares and cash out after five years. It also stated that a deposit of $2.5 million would be provided and upped to $12.5 million after it was countersigned, with a closing after a 60-day due-diligence process.

The version obtained by The Post and signed with Sitt’s squiggle had a response date of Sept. 15, 2013.

Meister’s father, lawyer Stephen Meister, is representing the opposing stakeholders, and states in a letter to Malkin’s lawyer, also obtained by The Post, that the bid is over both the appraised and exchange values in the proposed REIT and urged them to give “urgent and serious consideration” to the offer.

The Meister letter also requested a Lazard Frères & Co. report referred to in a Sept. 6 regulatory filing that was the basis for the Malkins rejecting the previous offers and moving forward with the REIT.
No one was available to comment.