Russell Clark’s entry into the high-stakes world of investing could hardly have been less promising. As a graduate trainee at UBS Group AG in Sydney, he was wowed by friends getting rich by day-trading tech stocks in 2000. So he spent his first few paychecks on five dot-com shares. Four crashed to zero, and the fifth lost half its value as the tech bubble burst. That lesson was so brutal that it helped turn Clark, now 45, into a career contrarian. These days the hedge fund he runs for London-based Horseman Capital Management is prepared for a market crash.