Motor racing-Hollinger raises stake in Williams F1 to 10 pct

By Alan Baldwin OXFORD, England, Feb 25 (Reuters) - American healthcare executive Brad Hollinger has increased his stake in the Williams Formula One team to 10 percent after exercising an option to buy more of Mercedes motorsport head Toto Wolff's holding. Speaking at a media briefing attended by Hollinger and Williams chief executive Mike O'Driscoll, Wolff said the private transaction left him with "just short" of five percent in the former champions. "I have no plans to change it," added the Austrian, who led Mercedes to both titles last year while Mercedes-powered Williams climbed from ninth in 2013 to third. The deal was expected after Wolff sold an initial five percent stake to Hollinger in June last year as part of an agreement with Mercedes parent company Daimler to reduce his shareholding over time to a purely investment level. Wolff was previously executive director at Williams, where his Scottish wife Susie is a test driver, before moving to Mercedes in January 2013. The latest deal puts Hollinger level with Williams co-founder Patrick Head as owner of 10 percent of the team with principal Frank Williams having a 52 percent stake and Wolff five. Of the remaining shares, 20 percent are listed on the Entry Standard of the Frankfurt Stock Exchange and a further three percent are held by an employee trust. Hollinger, the chairman and chief executive of Vibra Healthcare and a motor racing enthusiast, said he "would not preclude" increasing his involvement further but had no plans to put branding on the car. The American entrepreneur, who owns and races historic cars including a 1997 Williams, said he was investing for financial reasons and felt the sport could be "on the cusp of another major explosion" in growth. "I am never in business not to make money," he said. "I think there is a huge opportunity in Formula One. "It has not really tapped significantly the whole social media route in terms of streaming information out to the masses on whatever medium you might choose," he added. "Formula One has been incredibly successful despite the fact it has not really taken hold significantly in the U.S. and I think the opportunity exists...I think the future is really bright in the United States." Formula One now has an established U.S. Grand Prix in Austin, Texas, with commercial supremo Bernie Ecclestone eager to add another venue, possibly in Las Vegas after failed attempts by New Jersey. (Editing by Amlan Chakraborty)