Nielsen Holdings said that COO Brian West has resigned effective Dec. 31, 2015.
The company said that next year, West’s responsibilities will be divided among existing company executives.
West was named COO in 2014. He joined Nielsen in 2007 as chief financial officer and was a key figure when the company went from being privately held to public in 2011.
Before Nielsen, West was with General Electric, working in the conglomerate’s plastics, aviation and NBCUniversal divisions.
"We are grateful for all of the contributions Brian has made in his eight years at Nielsen as both CFO and COO," a Nielsen spokesman said. "We wish him well in his next endeavor."