Former chief executive Martin Sorrell says he still holds great interest in the fortunes of WPP since his departure last year.
"I remain a shareholder, and I think I'm the largest individual shareholder or a top 10 shareholder, in WPP so I'm very concerned about the progress that WPP makes too," Sorrell told CNBC Tuesday at the World Economic Forum (WEF) in Davos, Switzerland.
"Obviously it's not been an easy period over the last six months or so in terms of major clients at WPP but having said that we're very focused on that progress," he said.
Sorrell left the WPP empire he built nearly a year ago after an allegation of "personal misconduct," which he denies. His abrupt departure from an agency he ran for 33 years, and concerns over wider global growth that prompted clients to cut ad spending, has impacted the agency badly with sales and its share price dropping. Shares were down by around 37 percent in 2018 in what was a difficult year for many firms.
Sorrell remains the eighth biggest shareholder in the firm, according to Reuters data, with a holding of around 1.4 percent.
In December, WPP said it planned to spend £300 million ($385.9 million) over the next three years to return the world's biggest advertising group to growth by reducing the number of agencies it runs and hiring more talent in New York, according to Reuters.
Speaking to CNBC Tuesday, Sorrell said the company had "investigated the background to it (the allegation) and found nothing material. "We moved on from then and I decided to go off and start something new," he added.
Sorrell's new ad network, S4 Capital, is "very focused" on "the digital part of the market," he said, equating it to around 20 percent of the total advertising and marketing services market.
"We're focused on three things: First-party data, digital content and programmatic media planning and, last but not least, is programmatic media planning and buying," he said.
The agency has been on an acquisition spree in recent months, looking for digital-only assets. Sorrell's start-up outbid his former company to buy the Dutch agency MediaMonks last July and snapped up U.S. outfit Mighty Hive in December, as part of a strategy to focus on content and programmatic commercial advertising.
"That focus on digital, (a) faster, better and cheaper (market) and having a unitary structure are pretty key in the environment we're going into in the next couple of years," he said.