Tim Kendall, Pinterest’s top business executive, is leaving the company

Tim Kendall, Pinterest’s president and its most important business executive, is leaving the company at the end of the year.

Kendall, who has been with Pinterest more than five years and oversees all of the company’s advertising products, sales and marketing efforts, is leaving to start his own company in the health care space. The move was announced internally Thursday morning.

Jon Alferness, a former Google executive who joined Pinterest this summer to lead ad products, is taking over Kendall’s responsibilities. Alferness will report to Pinterest CEO Ben Silbermann, and Kendall will stay in touch with the company in an advisory role.

“Tim has made important contributions to Pinterest and we are pleased that he will continue to serve as an advisor to the company,” a spokesperson wrote as part of a statement provided to Recode. “Jon Alferness, Senior Vice President for Ads and Commerce, will now lead the world-class team driving our rapidly growing ads business.”

Kendall’s loss is a big one for Pinterest. Not only did Kendall oversee the company’s entire business operation, but multiple sources familiar with the company expect Pinterest to begin the IPO process sometime in 2018. Kendall would have been a public face for Pinterest’s business during this process, responsible for pitching the company to bankers and investors alongside Silbermann and CFO Todd Morgenfeld.

But that is, in part, why Kendall is leaving now, according to a source familiar with his decision. The closer Pinterest gets to an IPO, and the deeper it gets into conversations with potential partners in that process, the harder it would have been for him to leave.

Plus, Kendall will still benefit financially from an IPO even if he’s not working at the company. He’s been at Pinterest almost six years, which means he’s already vested whatever early stock package he received. Those packages typically vest after four years.

Kendall, who worked at pre-IPO Facebook for more than four years before joining Pinterest, has long had an interest in starting something on his own. He’s a bit of a health nut, especially when it comes to mental health. He takes daily ice baths, for example, for physical rejuvenation but also for the mental clarity he says comes from the shockingly cold water. He also refuses to look at his phone during meetings, and forbids others from doing the same.

Perhaps unsurprisingly, then, his new startup will focus on fighting device addictions, like an obsession with a phone or laptop, and the health concerns that come with them, according to a source.

It’s unclear what Kendall’s departure will mean for Pinterest’s business long term. The company was targeting more than $500 million in revenue this year, up from roughly $300 million in 2016. Investors will want to see that growth continue when the company starts the IPO process.

This article originally appeared on Recode.net.