Tim Armstrong, CEO of Verizon subsidiary Oath, will step down from his role on 1 October but stay on as an adviser until the end of the year, as president and COO Guru Gowrappan prepares to take his place.

The outgoing chief will guide Oath’s management transition efforts as a strategic adviser reporting to Verizon chairman Lowell McAdam, the operator said in a statement.

Gowrappan has been Oath’s president and COO since April and before that was global managing director at Alibaba Group.

He will “lead the next phase of Oath’s global growth strategy,” as the integration of AOL and Yahoo operations, and advertising technology platforms near completion under Armstrong’s direction, the company added.

Verizon CEO Hans Vestberg said: “Guru has proven experience in scaling businesses globally. I’m thrilled he will lead Oath in an exciting new phase of growth, building on the foundation Tim and his team have created by delivering brands our customers love.”

A report in The Wall Street Journal (WSJ) last week stated many of Armstrong’s day-to-day responsibilities were recently passed to Gowrappan.

Armstrong joined AOL in 2009 and was named Oath’s CEO in 2017. He has led Verizon’s digital media and online advertising platform business, along with the growth and development of consumer brands including AOL, Yahoo, TechCrunch and HuffPost.

The WSJ report said part of the reason Armstrong is leaving is a disagreement between Verizon and Oath executives over how much wireless subscriber information should be used for the advertising platform.

Oath’s advertising business has failed to achieve significant growth since its launch in June 2017. Revenue of $1.9 billion in Q2 was flat sequentially and down slightly on the $2 billion earned in Q3 2017, the unit’s first full calendar quarter.