Capstone signed a 10-year lease for 12,000 square feet, the entire 15th and 16th floors, at the Park House, owned by a joint venture of Principal Global Investors and Mermel & McLain, which bought the building in mid-2007 for $140 million.

Perhaps Capstone, whose rep didn’t return our requests for comment, was lured to the other side by the winning tower’s recent $5 million capital campaign, which, despite the relatively low dollar amount in real estate terms, revamped the most-noticed portions of the 20-story tower’s body: There’s a newly redone plaza entrance on 40th Street, a renovated lobby, a modernist mural by Sarah Morris and new elevator cabs, with the now requisite flat-screen TVs streaming financial news.

“I think the tenant was drawn to the building because of the recent renovations and because of the boutique tower floors, which offer a full-floor presence to the tenant and great light and views of Bryant Park,” said Paul Amrich, executive vice president at CB Richard Ellis, whose team represented the landlord.

Marc Miller, a broker at Winoker Realty, represented Capstone, and CBRE’s Mr. Amrich, Fernando Urrutia, Keith Caggiano and Michael Movshovich represented the landlord, with Mermel & McLain.

drubinstein@observer.com