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.

Let's start with Under Armour. The maker of sweat-shaking performance apparel and other athletic footwear and accessory items soared after posting another quarter of blowout results. Revenue soared 35%. Earnings didn't grow as quickly, but it was still a strong beat on both ends of the income statement. Under Armour also boosted its outlook for fiscal 2014.

Mobile marketer Millennial Media popped after announcing encouraging preliminary results for the holiday quarter. The company sees revenue clocking in between $106 million to $109 million, up from its earlier forecast calling for no more than $100 million in revenue. Investors also got excited in learning that a new CEO -- the former chief revenue officer at Yahoo! -- is stepping in to lead the fast-growing provider of display advertising solutions for mobile devices.

YRC Worldwide moved higher after the Teamsters union cleared the way for the leveraged trucking transport giant to swap $300 million of debt for equity. The move also opens the door for YRC Worldwide to refinance its hefty $1.4 billion in debt at more attractive rates.

Sequans Communications moved higher after an analyst upgrade. Robert W. Baird is upgrading the shares -- from "neutral" to "outperform" -- and dramatically boosting its price target from $2 to $5. That may not seem like a lot, but the new $5 price target represents 85% of upside from here.

Violin Memory has been a dud since going public at $9 less than five months ago, but it was singing a new tune after an activist shareholder told Bloomberg that the flash memory specialist has received informal buyout inquiries. Clinton Group doesn't know the identity of the interested buyers, but just the speculation was enough to give one of last year's worst IPOs a rare week to the upside.