Global ad tech provider Simzek has announced the appointment of Xaxis co-founder Mark Grether as it new global chairman to replace outgoing president and CEO Neil Nguyen.

As the co-founder and former global chief operating officer of Xaxis, Grether joins Sizmek with a wealth of agency experience across a variety of industry verticals, including automotive, retail and consumer packaged goods.

Prior to his time at Xaxis, Grether was the global development director of GroupM.

Simzek managing director Alex Beregovsky said the company was excited to welcome Grether to the team.

“He’s an accomplished executive with deep experience building and scaling up global companies, particularly in the digital media and advertising space,” Beregovsky said.

“We look forward to working with Mark to accelerate Sizmek’s growth and success.

“We sincerely thank Neil for the great legacy he leaves at Sizmek and wish him all the best in his new endeavors.”

Nguyen described his 13-year tenure at Simzek as “amazing and richly fulfilling”.

“I’m truly grateful to all of our global employees, my talented leadership team, our partners and clients around the world for the opportunity,” he said.

“We closed out 2016 with strong results and are proud of what we were able to achieve.