(Reuters) - Mercedes motorsport head Toto Wolff has sold a five percent stake in the Williams Formula One team to American healthcare executive Brad Hollinger, the Austrian said on Friday.
Hollinger, the chairman and chief executive of Vibra Healthcare, also has an option to buy more of Wolff's remaining 10 percent holding.
"It was always the plan to reduce the shareholding in Williams towards a level that is clearly a financial investment," Wolff told reporters at the Austrian Grand Prix.
"This was important to Daimler for conflict of interest reasons and for compliance reasons.
"But it was quite a task to find somebody who was good for the company, who was good for the family, and who had the spirit I had when I joined Williams as a financial investor," added Wolff.
Wolff was executive director at Williams, where his wife Susie is a development driver, but left in January last year to take up his new role at rivals Mercedes - now the dominant team in Formula One.
He gave a commitment at the time to Mercedes that he would sell his shares, but only once he had found a purchaser acceptable to Williams.
"I cannot just go into the market and say 'who wants to buy these shares?' and that's it. If I sell, I have to find somebody who is responsible enough, who is coming in for the sport, who understands how the team functions," he said last year.
Williams were listed on the Entry Standard of the Frankfurt Stock Exchange in a March 2011 public offering of around 21 percent of the existing shares. Wolff has been a shareholder since 2009.
Team founder Frank Williams remains the majority shareholder with a controlling interest in the British-based team with co-founder Patrick Head having a nine per cent stake.
The BBC quoted deputy team principal Claire Williams as saying her father had "no interest in further diluting his existing shareholding".
The autosport.com website quoted Hollinger as saying he felt Formula One, which has a successful grand prix in Austin, Texas, and would like a second race in the United States, was "right on the cusp of another explosive growth path".
"The whole social media element is an opportunity that F1 can really tap in to and accelerate even more," he added. "I think it will create an opening for the US market and I would like to be involved in that process as well."
(Reporting by Alan Baldwin, editing by Pritha Sarkar)