Manhattan’s largest office landlord is asking a court to make one of its tenants cough up millions of dollars in rent.

SL Green is alleging that Tennor Holding B.V. owes $15M in unpaid rent and compensation for the space it occupies in the crown jewel of the landlord’s portfolio, One Vanderbilt, according to a lawsuit filed in New York Supreme Court on Wednesday.

Tennor has been a tenant in the fully leased office tower since 2022, according to the complaint.

The global investment holding company in January 2022 signed a full-floor, 25K SF deal on a 10-year term. It was originally due to start occupying the space in June 2023.

At the time Tennor signed its initial lease at One Vanderbilt, which now commands some of the highest asking rents in the city, it also signed for a temporary 7K SF lease on the 54th floor. That lease ran from January 2022 through mid-June the following year.

But in September 2022, SL Green alleges that Tennor defaulted on the rent for the temporary space. The pair reached a settlement over the temporary space that included permission for Tennor to stay put, and they went on to ink two extension agreements that allowed Tennor to stay until July 31, 2024.

But Tennor later defaulted on its rent for both spaces and hasn’t paid rent since August 2023, SL Green alleges.

SL Green terminated Tennor’s lease in January 2024 but alleges that the tenant now owes $13.8M plus $1.7M in additional rent.

SL Green and Tennor didn't immediately respond to Bisnow’s requests for comment.

Space in Manhattan’s trophy office buildings is getting harder to come by, with availability below 12% at the end of the first quarter. In Midtown, that dropped to 7.5%.

One Vanderbilt reached 100% leased in September when it signed a 6K SF lease at $265 per SF. SL Green’s Manhattan office portfolio is 92.5% leased, the company said in its annual report for 2024.