One in 10 UK CEOs has over 20 years' experience The findings suggest that America is much better at nurturing and retaining key figures at the top than Britain, whose top companies tend to rely more on poaching the best chief executives rather than growing their own, the global analysis of 1,049 listed companies with a market cap of at least £2.7bn, revealed. Warren Buffett, the billionaire US investor, is the longest-serving chief executive globally, with 43 years in the role, followed by Ian Cumming, the chairman and chief executive of Leucadia National, an American holding company, with 35 years" service. The research has been published to mark the launch of the World of CEOs website, of which Telegraph Media Group is media partner, which will offer comprehensive and comparable profiles of over 4,800 chief executives worldwide. The site makes it easy to search the world's top business figures by country, sector, age and tenure, and provides "impartial" executive profiles. Steve Tappin, a former headhunter who set up the World of CEOs, said the site is aimed at small to medium-sized firms, which are interested in forming partnerships with, or understanding better, the biggest market players in the market, and for senior managers and professionals who want to interact with their peers. Mr Tappin said: "Information out there currently on CEOs is segmented and it's hard to trust the quality of it. The World of CEOs service puts all the information about the top CEOs in one place. Users can also personalise information according to their interest, he said. The study also shows that almost 40pc of America's chief executives are aged between 60 and 90, compared to just 14pc of Britain's bosses in this age group. Visit the world of CEOs website at worldofceos.com