Aby Rosen's RFR Holding has filed a lawsuit in Manhattan Supreme Court seeking to void a $6 million contract that would let SL Green Realty buy roughly 3,600 square feet of air rights from a residential condominium at 5 East 44th Street, the latest flashpoint in an escalating feud between the two Midtown developers. RFR is also asking a judge to block the condo board from amending its bylaws to get around Rosen's veto power over the sale.
The lawsuit centers on a small but strategically loaded transaction. As reported by The Real Deal, RFR bought a $1 million apartment inside the 5 East 44th Street condominium building in December, giving it standing as an owner. The building's bylaws require unanimous approval from every owner for a sale of air rights, and Rosen has refused to sign off, effectively holding SL Green's plans hostage over a single unit.
The condo board has pushed back by scheduling a special meeting for August 13 to consider amending its bylaws so that a supermajority of owners, rather than all of them, could approve the sale to SL Green. RFR's lawyers argue the board is acting beyond its authority, and it remains unresolved whether that vote will survive Rosen's legal challenge, according to the same report. A representative for the condo board did not immediately provide comment when reached, per the outlet.
A Bidding War Over Air Rights
SL Green has agreed to pay $6 million for the air rights and offered a 10 percent deposit, but RFR countered with a $6.5 million bid, exceeding SL Green's offer by $500,000, and agreed to put down a 20 percent deposit. The condo board rejected RFR's offer anyway, according to the same account, leaving Rosen to pursue the courts instead.
The air rights matter far beyond their price tag. Under New York City's 2017 Greater East Midtown Rezoning, folding 5 East 44th Street into a combined zoning lot lets SL Green tap density bonuses reaching up to 26.0 Floor Area Ratio, unlocking over 41,000 square feet of development rights while leaving the existing 22-story condo structure untouched, according to PincusCo. Standard base commercial zoning in the district provides only 15.0 FAR, and the seed reporting indicates the transferred air rights could generate roughly 37,000 square feet of development rights through the Midtown East rezoning bonus. Any such air-rights transfer in the district also triggers a mandatory 20 percent contribution from the sale value into the city's Public Realm Improvement Fund, which finances sidewalk widenings and transit upgrades around Grand Central, per the NYC Department of City Planning.
The Supertower at Stake
The air rights are meant to feed SL Green's planned tower at 346 Madison Avenue, the former Brooks Brothers flagship site. Designed by Kohn Pedersen Fox, the project is planned as a 46-story, 962-foot-tall all-electric office tower with roughly 850,000 rentable square feet, targeted for completion in 2031, according to Mori Building Co., the Tokyo developer that closed on a 49 percent joint venture stake in the project in May at a $175 million property valuation, as Hoodline previously reported. SL Green retained 51 percent control and serves as the project's development and leasing manager. A spokesperson for SL Green called the lawsuit frivolous and said it will not affect 346 Madison Avenue, with the project remaining on track and on schedule, per the outlet's report.
SL Green acquired 346 Madison Avenue and the adjacent 11 East 44th Street building for $160 million in November 2025. Former owner Claudio Del Vecchio had originally purchased the two properties in 2007 and 2019 for a combined $243.3 million, according to Commercial Observer, meaning he sold at a steep loss that let SL Green acquire the core development site at a discount.
A Rivalry With a Long Paper Trail
The air-rights fight is only the newest round in a bitter, multi-front rivalry between SL Green's Marc Holliday and RFR's Aby Rosen along Madison Avenue. Rosen sued Del Vecchio after SL Green closed the 346 Madison deal, alleging the seller had used RFR's confidential due diligence to steer the property to SL Green instead. RFR characterized the alleged leak to a third-party portal as a Trojan horse that squeezed the firm out of the purchase, according to the same reporting.
SL Green escalated matters in June 2026 by suing RFR in New York State Supreme Court, seeking a two-year judicial license to access RFR's neighboring properties at 350 Madison Avenue and 10 East 45th Street for site demolition work after RFR allegedly ignored repeated access requests. SL Green claimed RFR's lack of cooperation threatened immediate and irreparable construction delays. Rosen owns 350 Madison Avenue next door to SL Green's development site and had tried to buy the property himself when it was previously offered for sale.
Despite the litigation, Rosen has struck a conciliatory note in public remarks, saying RFR is excited about both SL Green's development at 346 Madison Avenue and RFR's own project at 350 Madison Avenue. He has even proposed joining forces with SL Green to deliver one larger, more efficient supertower rather than two competing structures. Rosen framed the current dispute as being about condominium owners' rights, saying RFR supports transparency from the condo board and will protect every owner's best interests.
RFR's Broader Portfolio Pressure
The lawsuit lands amid wider financial strain on Rosen's firm. In January 2025, a New York state judge ordered RFR to vacate the landmark Chrysler Building after landlord Cooper Union established that RFR had defaulted on $21 million in rent and ground obligations, Hoodline reported at the time. Cooper Union subsequently retained Cushman & Wakefield and Savills to manage the skyscraper.
RFR also fell behind on the mortgage for its vacant 23-story office building at 522 Fifth Avenue, a debt that SL Green had acquired at a significant discount and pursued through foreclosure proceedings. The two firms ultimately settled the case, and RFR sold 522 Fifth Avenue to Amazon, a resolution Rosen described as a major win for his firm. SL Green, meanwhile, has been recycling capital across its own portfolio, having announced a plan earlier in 2026 to sell roughly $2.5 billion in Manhattan assets to pay down corporate debt, including its 1350 Sixth Avenue tower, which Hoodline detailed in March.
For now, the fate of the 5 East 44th Street air rights hinges on the condo board's scheduled August 13 bylaw vote and whether it can withstand RFR's court challenge. SL Green maintains the litigation changes nothing about its timeline for the 346 Madison Avenue tower, while Rosen's legal team continues to argue the board overstepped its authority in trying to work around his veto.
