Local real estate firm Arden Group, founded by Craig Spencer, on Tuesday sold the 19-story Center City property 1635 Market Street to New York real estate investment firm Nightingale Properties, for an undisclosed price.

Nightingale's CEO, Elie Schwartz, has committed $5 million to renovations, starting immediately. Real estate agents with CBRE in Philadelphia, Kevin Maloney, Mark Adzick, George Cauffman, and Joe Wolff, will market the property.

"This is an exciting opportunity for this building. The owner is committed to transforming 1635 Market into a modern, high tech facility," said Maloney, vice president in CBRE's center city office, in a statement. "It could potentially house a single tenant on 86,000 square feet across six floors."

Nightingale Properties, founded in 2005 by Schwartz and Simon Singer, also owns 1835 Market Street, which it purchased this month for $100 million, 1700 Market Street, and 1500 Spring Garden. The 1635 Market building is a 286,574 square feet originally developed as regional headquarters for IBM. Planned improvements include renovating the facade, the main lobby, concourse, elevators, common corridors and bathrooms.