After 14 years as the chief operating officer of Facebook's parent company Meta, Sheryl Sandberg is stepping down, a huge shake-up that will see chief executive Mark Zuckerberg lose one of his closest lieutenants.

Sandberg, 52, has been one of Silicon Valley's most powerful women, and her exit comes as the social media behemoth confronts a challenging future and severe competition.

Sandberg announced her resignation as chief operating officer on her Facebook page, although she will continue on the board of Meta, the firm's parent company.

“Today, I am sharing the news that after 14 years, I will be leaving Meta,” Sandberg said in a social media post.

“I am beyond grateful to the thousands of brilliant, dedicated people at Meta with whom I have had the privilege of working over the last 14 years. Every day someone does something that stops me in my tracks and reminds me how lucky I am to be surrounded by such remarkable colleagues.”

“It's the end of an era,” CEO Mark Zuckerberg said in a Facebook post. “I’m going to miss running this company with Sheryl.”

“She has taught me so much and she has been there for many of the important moments in my life, both personally and professionally.” 

Sandberg's resignation comes as what began as an online social network rebrands itself as the metaverse, a virtual vision for the internet. In October last year, Facebook CEO Mark Zuckerberg announced that the social media giant will change the name of its holding company to Meta, and outlined the company’s virtual-reality vision for the future.

Sandberg's position at the firm will not be replaced, according to Zuckerberg, but Javier Olivan will take over as Meta's new chief operational officer. Over the last 15 years, Olivan has held several roles aimed at driving and managing the company's rapid growth.

But this role will be different from what Sheryl has done, said Zuckerberg. 

“It will be a more traditional COO role where Javi will be focused internally and operationally, building on his strong track record of making our execution more efficient and rigorous. As part of this, Molly Cutler, our VP Strategic Response, will join Javi's team and report to Naomi Gleit.”