Guy Hands, a European private-equity pioneer, says his confidence is shaken more than 10 years after a very public deal collapse. And although the businessman feels that he may never recapture his mojo, he believes his past stumbles have been a boon.

Hands, who years ago struck a more prominent figure within the private-equity community, blew £1.75bn in 2007 by investing in UK music company EMI Group, which counted Coldplay among its acts.