Viacom renewed and expanded at 1515 Broadway this past April.

NEW YORK CITY-SL Green Realty Corp. announced Tuesday that it has closed on a $900-million first mortgage refinancing of 1515 Broadway. Through a spokesman, the company declined to divulge who provided the financing.

The new 12-year, 3.93% fixed rate mortgage financing replaces the former $775-million mortgage loan that carried a seven-year term. SL Green will recognize approximately $116 million in net proceeds from the transaction. Skadden, Arps, Slate, Meagher & Flom LLP acted on behalf of SL Green. Sidley Austin LLP represented the lender group.

Says Andrew Mathias, president of SL Green, in the announcement, “Our ability to execute long-term fixed rate financing at historically low rates is a significant achievement and reflects both this property’s strength as well as the continuing positive evolution of Times Square. The long-term renewal of the Viacom lease, coupled with our redevelopment of the building’s lobby, common areas, retail space, and the introduction of LED signage, has created significant value.”

The refi follows the April 2012 renewal by Viacom of 1.6 million square feet at the office tower through 2031. As previously reported, that deal marked an expansion for the media company and was believed to be the largest-ever New York City office lease, other than a few sale-leaseback arrangements.

Known for its studio overlooking Times Square, and the parent of a long list of networks that includes MTV, Nickelodeon, BET, Comedy Central and TV Land, among others, Viacom will take the balance of its building’s office space after 2020. At the time of the Viacom deal, SL Green CEO Marc Holliday said the broadcaster signed the deal because of its longstanding presence in Midtown.

“The company has been a corporate anchor in Times Square for over 20 years and the extraordinary building branding opportunity provided in this lease will allow Viacom to increase its corporate visibility to millions of New York City visitors at the ‘Crossroads of the World’ for years to come,” he said in a statement. “The transaction reaffirms the desirability for trophy assets located in the prime areas of Midtown Manhattan.”

SL Green declined to provide further comment on the latest round of financing and it was unclear whether the REIT waited to pursue the refinancing until it had locked in the Viacom renewal or whether it was already working to refinance when Viacom signed on. Either way, SL Green clearly seized upon an opportunity after the building’s value had increased.

As of December 31, 2012, SL Green owned interests in 85 Manhattan properties totaling 40.8 million square feet.