The European banking industry has outperformed its American rivals in 2011, but the good times may be set to end, with investors increasing their bets against the sector as worries over the Portuguese bailout and tougher banking rules mount, new data shows.

According to a note published today from Russell Investments, financial services shares in the Russell Europe Index gained 15.5% in 2011 to April 8. That compares with returns of only 4.2% in the US broad-market Russell 3000 and just 0.7% in the Asian financial sector within the Russell Asia Pacific Index.