Douglas Durst’s budding Bank of America Tower on 42nd Street has netted another lease agreement and is only a floor away from being fully leased, some eight months before the 54-story skyscraper opens its doors.

The law firm Akin Gump Strauss Hauer & Feld has an agreement with the Durst Organization to take the 47th floor, a source said. This means that Akin Gump adds to its monstrous block of roughly 230,000 square feet between floors 41 through 47.

The only space available for rent is the building’s 37th floor, which Bank of America, the biggest leaseholder in the tower, gave back to Mr. Durst earlier this year.

The source would not comment on rent totals for the 47th floor, but it’s unlikely that Mr. Durst received the $185 per foot that he was seeking earlier this summer. Since Akin Gump had already committed to significant space in the tower, there was probably a favorable arrangement for both parties (though that certainly means that Akin Gump paid much more for the tower floor than the roughly $100 per foot it paid for the 203,000 square feet it rented in July 2006).

For Mr. Durst, things couldn’t have worked out better. In 2004, he told The New York Post that rents for the building “will have a 1 in front of them,” a bold statement at a time when midtown rents were only occasionally touching the triple-digit mark.

Three years later, in a record-breaking year for Manhattan office rents, he has easily reached that goal. Really, the only problem for Mr. Durst is that he doesn’t have more floors available for rent. When Marathon Asset Management signed its lease in January, a source at the time said rents were around $115 per foot. It was only six months later that Mr. Durst started asking for $185 per foot.

Within real estate circles, the Bank of America Tower—also known as One Bryant Park—has been an incontrovertible hit. The real estate magnate Kent Swig told the trade journal National Real Estate Investor last week that he believed Mr. Durst would receive “astronomical returns” on the tower, describing everything from Mr. Durst’s financing to the rent levels he’s attained as “phenomenally successful.”

Mr. Swig isn’t the only one drooling, especially as the next legion of Manhattan skyscrapers—the SJP tower at 11 Times Square, the Macklowes’ project at 440 Park Avenue, the Mort Zuckerman tower on Eighth Avenue—go up in an uncertain market.

Mr. Durst will have a good view of those construction projects, too—from his 49th floor office at Bank of America.