• Another high-profile Instacart executive is leaving the grocery delivery service company.
• Carolyn Everson announced Friday she will step down as president at the end of the year.
• The surprise decision comes three months after Everson started and follows the exit of a second top executive in October.

Instacart president Carolyn Everson said Friday she will step down at the end of the year, just three months after she joined the grocery delivery service company.

The latest shake-up in Instacart's C-suite follows the exit of the head of advertising, Seth Dallaire, who left for Walmart in October. The company has hired several big tech executives from Facebook (now Meta), Amazon and Google. Even though Instacart's valuation has grown quickly to nearly $40 billion this year, some of the newcomers, including Everson, are used to running far larger teams. 

Everson spent more than 10 years at Facebook as its ads chief and was Instacart CEO Fidji Simo's most high-profile hire. Simo, the former head of the Facebook app, took over from founder Apoorva Mehta earlier this year.

Everson was seen as one of the most prominent women behind Facebook's COO Sheryl Sandberg, but she left the company after Marne Levine — not Everson — was promoted to chief business officer last summer.

Simo and Everson told CNBC the decision was mutual. 

"We believe it's the right decision for both the company and Carolyn based on our priorities and the role she was looking for at this point in her career," Simo said in a statement. "She'll be staying on with us through the end of the year, and leaves as a friend to the company."

Everson oversees several divisions at Instacart, including advertising, partnerships, policy and legal.

Instacart has cited its advertising business as one of its fastest-growing segments, but it's looking to push into cash-intensive business of quick commerce, or 15-minute delivery, to compete with the likes of DoorDash and GoPuff, according to sources who asked to remain anonymous because they aren't authorized to speak publicly. The plan to trial 15-minute delivery was first reported by The Information.

Instacart was widely anticipated to go public this year but reportedly pushed back plans to focus on growth under new leadership. 

Everson said in a Facebook post that, as her 50th birthday approaches, she will take time off before deciding on her next step.