NEW YORK CITY-SL Green Realty Corp. said Friday it has bought out City Investment Fund’s 49.9% stake in 521 Fifth Ave., assuming full ownership of the 490,000-square-foot office property. The transaction values the consolidated interests at $245.7 million, or about $502 per square foot, according to a release.

SL Green had bought the 39-story tower from RFR Realty in 2006, via a long-term net leasehold interest. Later that year, the REIT entered a recapitalization agreement with CIF in which CIF acquired a 49.9% interest. The partners then spent $26.7 million to reposition 521 Fifth with a new lobby and other building upgrades.

Andrew Mathias, SL Green’s president, says in a release that the deal concludes “another successful joint investment with City Investment Fund, which also has been a valued partner at 19 W. 44th St. and 485 Lexington Ave.” SL Green has since sold 19 W. 44th, trading it this past September for $123.2 million. Mathias adds that the REIT anticipates bringing 521 Fifth “to full occupancy at increased rental rates.”

Matthias says SL Green’s joint venture platform “continues to serve as a proprietary pipeline for off-market deals that yield sizable transaction costs savings for both SL Green and our partners who wish to monetize their positions.” Other JV partners with which the REIT has struck deals include the Canada Pension Plan Investment Board, to which it sold its 45% beneficial interest in 1221 Ave. of the Americas for $577.4 million and with which it acquired 600 Lexington Ave. for $193 million, both in May 2010.