Extell Development sold the controlling interest in a pair of Chelsea buildings in a deal valued at $29 million, more than double what the Gary Barnett-led firm paid for the properties just six months ago.

The firm transferred ownership to an entity known as 717 Subsidiary LLC, which is controlled by A&H Acquisitions’ Alex Adjmi, property records show. The buildings include a three-story mixed-use building at 116 Seventh Avenue, as well as a four-unit residential building at 204 West 17th Street, according to filings. Combined, they offer 31,478 buildable square feet.

Adjmi confirmed that he acquired a controlling interest in the properties, but declined to comment further.

Extell bought the buildings last December for $11 million from Duell Management. To date, it has not filed permits for work at either site.

The two Chelsea buildings are among a string of properties Extell purchased from the family-run investment firm in December 2015.

In addition to the Chelsea buildings, Barnett paid Duell $11 million for 502 Third Avenue in late 2015. Earlier this year, Extell paid $20 million for a rental building at 27 Washington Square North in Greenwich Village, and it reportedly was also looking to scoop up 520 Sixth Avenue.