Morgan Stanley is leaving Wall Street. The firm was the largest tenant at the World Trade Center and lost nearly 1.2 million square feet of office space when the WTC was destroyed. It expects the vast majority of its 14,000 employees in New York City will remain in the city at its global headquarters in the 1.4 million-square-foot building it owns in mid-town.

The firm has a preliminary agreement with ChevronTexaco to purchase the site of Texaco’s former world headquarters, a 725,000-square-foot office building on 107 acres in Westchester County, New York. Terms of the transaction were not disclosed. The four-story building is located in Harrison, New York, 27 miles north of Morgan Stanley’s headquarters at 1585 Broadway in New York City.

Morgan Stanley plans to undertake significant renovations and technology upgrades at the Westchester facility, which was built in 1977, before it can relocate any businesses or employees there.