Social media company Pinterest has named an executive from top shareholder Elliott Investment Management to its board in a deal with the U.S. activist hedge fund.

Elliott Senior Portfolio Manager Marc Steinberg will join Pinterest’s board on December 16, an appointment that came after a monthslong ‘‘collaborative dialogue’’ with the activist firm, the company said on Tuesday afternoon.

As part of the agreement with Elliott, Steinberg is to be nominated for reelection at the company’s 2023 annual meeting for a term expiring in 2026. Steinberg’s addition will take the number of independent directors serving on Pinterest’s board to eight and the total count to 11.

Pinterest shares climbed 2.5% in after-hours trading Tuesday following the announcement. They gave up 5% in regular trading and are down 38% year-to-date. Elliott is Pinterest’s biggest investor, owning about 3% of common stock and an overall economic exposure of more than 9%.

Pinterest CEO Bill Ready described the partnership with Elliott as a “one-of-a-kind agreement” and said the social media company “appreciates the perspective” Steinberg, Elliott Managing Partner Jesse Cohn, and others at the activist firm bring.

After the news broke, Cohn took to Twitter to express his confidence in Pinterest’s value potential. ‘‘With its already strong foundation, healthy balance sheet and unique business model, we believe that Pinterest has only scratched the surface of the company’s potential’’ under CEO Ready, wrote Cohn.

Cohn has been involved in several prominent campaigns led by Elliott in recent years, including a June deal with Western Digital that saw the technology company agree to a strategic review.

The hedge fund, which oversees some $55 billion in assets, sometimes bids for companies that are targets of its activist campaigns. Steinberg serves on the board of Nielsen, the TV ratings group that was taken private earlier this year by Elliott’s private equity arm Evergreen Coast Capital.