Sizmek has appointed former Xaxis exec Mark Grether as executive chairman, following the departure of president and chief executive Neil Nguyen.

Grether, who previously acted as co-founder and chief operating officer of WPP’s Xaxis, will work with Nguyen through the transition period.

“Sizmek has developed a strong presence in the digital marketing industry, working to revolutionise how marketers and advertisers balance technology and creative on behalf of their clients,” said Grether.

“I’ve been impressed by the technological assets and product roadmaps, and I look forward to guiding the company and its leadership team and accelerating the growth of the business, while providing the highest level of service to our customers who rely on Sizmek’s open ad management capabilities for their multiscreen campaigns.”

Sizmek board member and managing director of the ad management company’s largest investor Vector Capital Alex Beregovsky described Grether as “an accomplished executive with deep experience building and scaling up global companies, particularly in the digital media and advertising space”.

“We sincerely thank Neil for the great legacy he leaves at Sizmek and wish him all the best in his new endeavours,” he added. “We look forward to working with Mark to accelerate Sizmek’s growth and success.”

Of his departure, Nguyen commented that he had had an “amazing and richly fulfilling 13-year journey”.

“I’m truly grateful to all of our global employees, my talented leadership team, and our partners and clients around the world for the opportunity,” he concluded. “We closed out 2016 with strong results and are proud of what we were able to achieve.

“I remain a big fan of Sizmek and under Vector’s ownership, as well as Mark’s guidance, the company is well positioned to continue to be a market leader in advertising technology.”

Meanwhile, Xaxis is rebuilding its leadership team through key appointments in EMEA and APAC regions.