STORY: The announcement initially sent the social media firm's shares down 4%, but the stock was nearly flat in after hours trade.

The second-in-command to founder Zuckerberg, she is one of the most visible executives at the company and the lead architect of its often-criticized ads business model.

Brian Wieser, the global president of business intelligence at GroupM, told Reuters via Zoom "Well clearly Sandberg has been instrumental in the rise of Facebook and now Meta's business much as she was critical for Google in earlier stages of that business. Where we are now is that the company has certainly matured in good and bad ways and so certainly there's a legacy there of having built up that infrastructure that makes the company the second larger seller of advertising on the planet."

Sandberg's departure marks an end of an era for Facebook-owner Meta, which is shifting its focus toward hardware products and the "metaverse" after years of scandals over privacy abuses and the spread of conspiratorial content on its platforms.

Wieser said "It's certainly clear based on all the comments and the plans for investment, not withstanding any minor set-backs that they may have announced that they are definitely trying to prioritize all things Metaverse going forward so there's a difference in the company but I think it's pure speculation to get really into the specifics of the timing outside of anything they've said. We just don't have a good reason to know anything beyond what's been said publicly."

Chief Growth Officer Javier Olivan will take over as chief operating officer, Zuckerberg said in a separate Facebook post, although he added that he did not plan to replace Sandberg's role directly within the company's existing structure.

Sandberg said in her post that she will continue to serve on Meta's board after leaving the company in the fall.