BALTIMORE (Stockpickr) -- Two trading sessions are all that stand in between us and April, and after the month we've had in March, investors are eager to welcome in a change. All told, the big S&P 500 index lost just over 2% over the course of the calendar month, which wouldn't be so awful if not for the fact that we started the month up the same amount.

Now we're about to end the first quarter of 2015 barely above breakeven. That's the worst start for the S&P 500 since the broad market bottomed in the first quarter of 2009.

But the good news is that some stocks are still working in this market. In fact, nearly one in five S&P 500 components is actually up double digits year-to-date. That's a massive chunk of outperformance -- but you've got to know where to look.

That's why we're pulling up a fresh list of Rocket Stocks this week.

For the uninitiated, "Rocket Stocks" are our list of companies with short-term gain catalysts and longer-term growth potential. To find them, I run a weekly quantitative screen that seeks out stocks with a combination of analyst upgrades and positive earnings surprises to identify rising analyst expectations, a bullish signal for stocks in any market. After all, where analysts' expectations are increasing, institutional cash often follows. In the last 292 weeks, our weekly list of five plays has outperformed the S&P 500's record run by 83.24%.

Without further ado, here's a look at this week's Rocket Stocks.

Mallinckrodt

Up first on the list is $15 billion pharmaceutical stock Mallinckrodt (MNK) - Get Report. MNK has been a major outperformer in 2015, rallying more than 30% since the calendar flipped to January. Yes, the whole health care sector has been looking strong this year, but Mallinckrodt has been a particular standout. And shares look likely to keep up that momentum as we head into April.

Mallinckrodt specializes in generic pain drugs, a specialty that comes with deep margins and a highly regulatory environment. The firm produces a big piece of the DEA's controlled substance quota. Mallinckrodt also has a growing branded drug and nuclear imaging business that it's been putting more emphasis on through acquisitions; the moat surrounding branded products is more defensible than generics, even if MNK's generic positioning is best in breed. Mallinckrodt isn't a new name, but it is new to the public markets as a standalone; MNK spun out from Covidien (COV) in 2013.

From a financial standpoint, Mallinckrodt is in decent shape. The firm has $900 million in cash and investments on its balance sheet, enough to offset some of its manageable $4 billion debt load. As long as MNK's management can resist the urge to buy expensive acquisition targets, this pharma stock is set up to keep outperforming in 2015.

Norwegian Cruise Line Holdings

Norwegian Cruise Line Holdings (NCLH) - Get Report is another large-cap stock that's off to a great start in 2015, up more than 15% since the first trading session of the year. A lot of that upside has come from falling fuel prices; operating a fleet of large cruise ships is energy-intense, so the huge haircut in oil prices over the last six months has been a positive, particularly if it persists long enough to outlive fuel hedges.

Norwegian is the No. 3 cruise line in the world, positioning that gives the firm lots of open runway to grow. On a relative basis, NCLH currently has more new ship capacity on order than its bigger peers, which means that the fleet is transitioning younger more quickly. As consumers look for the best experience on their vacations, a young fleet is a major driver of more frequent high fares. Meanwhile, NCLH operates 21 ships across three brands, with a skew towards the higher end of the cruising market.

Running a cruise line is extremely capital intense, but the recent combination of falling oil prices and interest rates near zero look to improve NCLH's fortunes in 2015. Considering that a new cruise ship can easily cost more than $1 billion, Norwegian's $6 billion total debt load isn't exactly jarring. There's a lot to like about this business right now.

Signet Jewelers

Retail jewelry store chain Signet Jewelers (SIG) - Get Report has been picking up some momentum in March. After a pretty weak start to the year, shares are up more than 13% since March 2, strikingly better performance than the S&P's loss over the same stretch. Signet operates more than 3,500 locations worldwide. The firm's brands include Kay, Jared, Zales and H. Samuel.

Though a series of consolidations, Signet has basically built a portfolio that includes the majority of the mass-market jewelry retail chains. The most recent of those was the acquisition of Zale Corp. at the beginning of last year, a move that dramatically boosted Signet's scale in the U.S. Conventionally, the jewelry business tends to be high-margin, and especially so in the mass-market side of the business, which has helped sustain net margins in the double-digits.

Low interest rates have been another boon for SIG. Because the firm's offerings tend to be big-ticket purchases, the ability to offer low financing rates is a major plus -- and part of why the firm expects same-store-sales to increase as much as 4% in the year ahead. Make no mistake, Signet is far from cheap right now, trading at 28-times earnings, but buyers have clearly grabbed control of shares this month.

Red Hat

At first glance, selling something free doesn't seem like a very good business strategy. But it's exactly how software stock Red Hat  (RHT) - Get Report managed to generate $1.79 billion last year. Red Hat is the company behind its namesake flavor of Linux operating systems, middleware and storage management tools, a collection of open-source products that grab around 60% of the Linux server market.

Red Hat doesn't charge licensing fees for its software. Instead, it earns revenue from training, maintenance, and tech support fees that it charges the businesses that use its software. Because licensing costs are effectively zero and customization costs far less for a big enterprise IT department, Red Hat's value proposition vs. a conventional server or workstation operating system is hard to argue with.

Because the infrastructure that runs Red Hat is mission-critical for businesses, switching costs are high for the firm's big installed base. And even better, the model means that RHT operates with low capital needs, no debt and deep margins. At last count, the firm carried approximately $1 billion in net cash and investments, enough to cover around 8% of its market capitalization at today's prices.

With rising analyst sentiment in RHT this week, we're betting on shares.

Columbia Sportswear

Last up on this week's Rocket Stocks list is Columbia Sportswear (COLM) - Get Report, the mid-cap outdoor apparel company. Columbia is another big name that's outperforming in a big way; today, this stock is 36% higher than it started in January.

Columbia Sportswear owns a handful of popular active apparel brands, including namesake Columbia as well as Sorel, Mountain Hardwear, prAna and Montrail. Make no mistake, that's a hard business to compete in. Consumers are fickle about fashion, and there's no shortage of well-capitalized brands looking to grab their attention. But Columbia owes a lot of its success to its market positioning -- the bulk of the firm's revenues are made selling at value prices without diluting the brand image. As COLM starts to focus on its higher-margin brands and on more lucrative products like trail footwear and outerwear, profits should keep moving higher.

From a financial standpoint, Columbia Sportswear is another well-positioned stock. The firm currently carries more than $440 million in cash on its balance sheet, with zero debt. That's about ten cents of every dollar you pay for shares of COLM today, paid for in cold, hard cash. This firm's big cash cushion and lack of balance sheet leverage helps to wring out some of the risks that come from investing in the active apparel business.

This article is commentary by an independent contributor. At the time of publication, the author held no positions in the stocks mentioned.