Square CFO Sarah Friar is leaving to become the CEO of Nextdoor — which means she won’t become the CEO of Square

Sarah Friar, the CFO of Square, is leaving the company to take the CEO role at Nextdoor, the social networking company that focuses on neighborhoods.

Square CEO Jack Dorsey shared the news Wednesday when he tweeted an internal memo that he sent to company employees.

“I’m saddened by the news. I was unrealistically expecting to work with Sarah well into our 90s,” Dorsey wrote. “Unrealistic because I knew of Sarah’s lifelong ambition to run her own company.”

The irony there is that many people did expect that Friar would eventually run her own company: Square. If you ask people close to Dorsey how he’s able to run two publicly traded companies — he is also CEO at Twitter — Friar’s name is often tossed out as an example of the kind of strong leadership he has surrounding him at Square to make that work.

Friar was considered by many to be a potential CEO candidate for Square if Dorsey ever decided to run Twitter full time.

Clearly that’s not going to happen now.

As far as CFOs are measured, Friar has had a very successful run. Since Square went public in late 2015, the stock has more than quintupled in price. It was down more than 9 percent in after-hours trading Wednesday on news of Friar’s departure.

Her challenge at Nextdoor will be different, at least for a while. Nextdoor CEO and co-founder Nirav Tolia announced that he was stepping down in July to “find a proven operator to take that company to the next level.” Nextdoor is still trying to grow its business and expand internationally before an IPO.

Square, meanwhile, will hunt for Friar’s replacement with the help of a few of its board members. David Viniar, former CFO of Goldman Sachs, and Roelof Botha, former CFO of PayPal, will “partner” on the search, Dorsey said in his memo.

Here’s Friar onstage at Recode’s Code Commerce conference last month.

This article originally appeared on Recode.net.