Fitbit Inc. announced that chief financial officer William R. Zerella will depart the company, effective June 15. The company has promoted Ronald W. Kisling, currently serving as chief accounting officer, to the role of CFO, leveraging his nearly four years with Fitbit to ensure continuity of operations.

Zerella served as Fitbit’s CFO since June 2014. During his tenure, he guided the company to one of the largest consumer electronics IPOs in history and scaled the company globally. Today, Fitbit has sold over 78 million devices and has a growing, active community of users of over 25 million, is in 86 countries and has a retail footprint across 47,000 stores. Zerella is leaving Fitbit to become CFO of an autonomous vehicle technology startup, leveraging his experience in growing businesses.

“Over the past four years, Bill’s passion and dedication to growing early-stage companies were key enablers of Fitbit’s transformation from a startup to the leading global brand it is today. We thank him for his countless contributions, including leading our successful IPO in 2015, guiding our worldwide expansion and laying the foundation for our future success, and wish him all the best in his next endeavor,” said James Park, CEO and co-founder of Fitbit.

As CFO, Kisling will lead Fitbit’s global finance organization, reporting to Park. He brings nearly 35 years of financial leadership experience to the role, having served as the CFO of multiple public and private technology companies. Prior to Fitbit, Kisling was CFO of Nanometrics, a publicly traded semiconductor equipment company. He also held senior executive roles at PGP Corporation, Saba Software and SPL Worldgroup. He joined Fitbit nearly four years ago as CAO, overseeing accounting, real estate & workplace and IT functions.

“Ron has long been an important member of our senior leadership team and we will continue to benefit from his significant expertise in leading sophisticated finance organizations as we position Fitbit for its next stage of growth,” said Park. “We remain confident in the long-term future of Fitbit and look forward to partnering with Ron as we execute on our plan.”

The company continues to execute on its transformation strategy and is making strides adapting to the changing wearable device market. Fitbit has experienced strong consumer demand for its new smartwatch, Fitbit Versa, and the company announced earlier this week that sell-through in the first six weeks of availability in North America was the best of any Fitbit device in the history of the company. Fitbit has increased confidence in its outlook that smartwatch revenue will be more than 50 percent of sales in the second half of 2018; therefore, revenue and earnings guidance for Q2 and fiscal year 2018 has been reaffirmed.