SL Green Realty Corp. is betting on itself, despite the poor performance of REITs in the past 18 months.

The largest office landlord in New York has been using the proceeds of building sales to buy back its own stock while it is trading far below the value of its own assets, the Wall Street Journal reports.

In December, SL Green set out a goal to buy back $1.5B of its shares, and has financed such buybacks by selling minority shares of some of its largest assets. It spun off 43% of its office building at 1515 Broadway to Allianz, and sold 27.6% of One Vanderbilt, its flagship supertall under construction across from Grand Central Terminal, to the National Pension Fund of South Korea. SL Green also sold 600 Lexington Ave. for $305M in November.

Concerns about rising interest rates have contributed to a precipitous decline in share prices across the board for REITs since 2016, with SL Green falling from as high as $119/share in August 2016 to just under $100 when trading closed Monday. Since it set out to buy back its stocks, however, the REIT has remained relatively stable.

SL Green CEO Marc Holliday told the WSJ that his company's buyback plan represents "the ultimate expression of confidence" in a future rebound — optimism that could be based in the tax reform bill that passed earlier this year. Its sale proceeds are not all to shore up its stock; SL Green continues to make purchases as well.

One Vanderbilt also has the potential to be a major revenue generator for SL Green, and the building signed law firm Greenberg Traurig to a lease for four floors of the building when it is completed in 2021.