Read 'Apple’s ‘most valuable’ crown at risk': on.ft.com/1X6Ud9K<br /><br />► Subscribe to the Financial Times on YouTube: http://bit.ly/FTimeSubs<br /><br />As Google again draws level with Apple as the world's largest company, John Authers looks at the historic performance of companies once they have become the largest.<br /><br />For more video content from the Financial Times, visit http://www.FT.com/video<br /><br /><br />Twitter https://twitter.com/ftvideo<br />Facebook https://www.facebook.com/financialtimes
