5 of Last Week's Biggest Winners

What's better than momentum? Mo' momentum. Let's take a closer look at five of this past week's biggest scorchers.

Source: Barron's.

Vical -- a biotech working on a metastatic melanoma treatment that's in the late stages of clinical studies -- popped nicely higher after impressing investors at the Cowen and Company 33rd Annual Health Care Conference in Boston on Wednesday.

MGIC wowed investors with a 39% surge a week earlier, and it kept the party going with a 30% climb this time around. Mortgage insurance companies have been soaring as the housing market firms up, since that means less risk for the values of the homes that they're insuring. Rival MBIA also went along for the ride, moving 21% higher this past week on the same wave of improving fundamentals.

James River Coal initially tanked after posting a wider-than-expected quarterly deficit, but its plans to idle a few mines should save money at a time when the coal producer can certainly use it. After slumping through the first four days of the week, James River burst into positive territory with a 17% pop on Friday.

Amarin posted a much smaller deficit than Wall Street was expecting two weeks ago, but momentum is building for this quarter's launch of its flagship Vascepa drug. The first approved medication for the treatment of high triglyceride levels should mean big things for Amarin, and having nearly 25 million shares sold short should add fuel to any rally.