“There are cases where I’ve made it clear to the developers that in order to start negotiations the settlement has to be in the eight figures per tenant,” said David Rozenholc, a lawyer who negotiated the Tishman Speyer deal on behalf of the tenants and has made such buyouts his signature practice.

Most buyouts are much smaller. Some are just a few thousand dollars, and are sometimes used to coerce poor, vulnerable tenants to leave. There are not many projects like Hudson Yards, Sherwin Belkin, a lawyer for Tishman Speyer, said.

“This is a unique site,” he said. “That’s what drives numbers like these.”

In that rarefied real estate niche, the size of buyouts is being driven up by the scarcity of land, the infusion of foreign investment and the immense expected financial returns.

Negotiating a buyout offer can be a painstaking process for lawyers like Mr. Rozenholc. They zero in on the development site as if they were tycoons planning to buy it. What are the carrying costs while the property sits idle? How much money do the owners stand to make on the project?

Other factors can give added leverage to tenants. If, like one of the apartments in the Tishman Speyer buyout, a unit is rent-controlled rather than rent-stabilized, the vagaries of the law make it almost impossible to dislodge a tenant.

The $25 million Tishman Speyer settlement over the site at the southwest corner of 10th Avenue and 35th Street was first reported by Crain’s and confirmed by a person with knowledge of the terms of the deal who was not authorized to speak openly of it. Buyout agreements usually come with confidentiality clauses, making it hard to assess how frequently single tenants get multimillion-dollar checks.