Boston Properties has agreed to sell 45 percent of its interest in three office buildings in Boston and New York to affiliates of Norges Bank Investment Management for $1.5 billion.

Boston Properties plans to form a joint venture with Norges Bank for each of the three properties, which include the 31-story, 791,000-square-foot Atlantic Wharf and 37-story, 1.3-million-square-foot 100 Federal St. in Boston and 1.7-million-square-foot 601 Lexington Ave. in New York City. Boston Properties will retain a 55-percent ownership share.

The new partnership is considering a redevelopment of the two-block 100 Federal St. property, including more retail space on the lower levels of the property. Boston Properties has been studying ways to enliven the area overlooking Post Office Square for two years, said Michael Walsh, senior vice president of finance.

"It’s made a huge transformation over the years and adding plaza-level retail would make it even more attractive," Walsh said.

One idea is converting the horseshoe-shaped driveway area in front of the Congress Street entrance into space for open-air dining, Walsh said.

Boston Properties acquired 100 Federal St. from an affiliate of Bank of America for $615 million in 2012. Boston Properties will remain the property and leasing manager of the three properties.

Eastdil Secured represented Boston Properties in the transactions. Goodwin Procter’s James Broderick, co-chair of the firm’s real estate investment management and finance practice, led the team advising Boston Properties.

In July, a joint venture of Norges Bank and MetLife acquired the One Beacon St. office tower in Boston for $561 million from Beacon Capital Partners and insurer Allianz. Norges Bank owns a 47.5 percent stake in the 37-story, 1-million-square-foot tower built in 1973 which was 85-percent leased at the time of acquisition. Norges, the world’s largest sovereign wealth fund, also acquired One Financial Center in Boston in January.