Mercedes Motorsport boss Toto Wolff has sold around a third of his shareholding in the Williams F1 team to an American businessman.

Wolff, who made the shock move to Mercedes in January 2013, retained a 15+ percent share in the Grove outfit despite the apparent conflict of interest, while his wife, Susie Wolff is a development driver with the British team.

Today it was revealed that Wolff has sold a slice of his shareholding to Brad Hollinger, Chairman and Chief Executive Officer at Vibra Healthcare which operates Acute Medical Rehabilitation hospitals and Long Term Acute Care hospitals in the United States.

"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 Red Bull Ring. "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," he admitted.

While his 5 percent holding will not give him any management involvement in the team, Hollinger, who has the option to buy further shares, says he believes the sport is on the verge of great things and therefore sees the purchase as an good investment.

The sale leaves team founder Frank Williams owning around 52% of Williams Grand Prix Holdings, team co-founder Patrick Head with 9% and Wolff with just over 10%, Hollinger on 5% and 23.7% on the stock market.

Chris Balfe