Harbor Group International, a Norfolk, Va.-based real estate company, is in contract to buy 4 New York Plaza from JPMorgan Chase for about $108.9 million or $99 a square foot.

Sources told The Post that Harbor Group is working with Josh Zamir’s Capstone Equities in a joint venture to buy the 23-story, 1.1 million square foot building located at Broad and Water streets.

According to an e-mail written by Zamir that was obtained by The Post, JPMorgan would lease back 75 percent of the building for 15 years. In that same e-mail, Zamir said he is “in contract” to buy the building.

Calls to JPMorgan and Harbor Group were not returned at presstime.

Capstone owns and manages over 8 million square feet including 14 Wall Street, while Harbor owns 14 million square feet of various property types in the US and Europe.

The deal comes as JPMorgan looks to unload 23 office buildings in eight states, including the 2.2 million square foot One Chase Manhattan Plaza downtown.

The bank had hoped to fetch $1 billion for the properties, but that might be tough given 4 New York is selling for one-quarter what it would have fetched at the height of the real estate boom.