DoubleClick agrees to Hellman & Friedman buyout

DoubleClick, the internet advertising company, has agreed to be bought by California investment group Hellman & Friedman for $1.1bn (&£570m) in cash. Hellman & Friedman’s last foray into the advertising world was the acquisition of 20 per cent of Young & Rubicam in 1996: it sold the stake in 1999 for a return of $1bn (&£520m) on its investment.