After bouncing up and down around the 13000 level for a week, the Dow Jones Industrial Average finally closed above that psychologically important mark for the first time since May 2008.

As last summer's fears of a U.S. recession and a European debt collapse have gradually waned, the Dow has staged a 22% rebound since early October, and its 6.4% gain for 2012 marks the strongest beginning to a year since 1998.

With...