There's a colossal rally taking shape in some of the biggest stocks on the market - but you've got to look beneath the surface of the big indices to see it.

That's because, while the S&P 500 has already managed to generate a respectable 2.5% gain year-to-date, the best-performing segment of the index is the one on fire right now. As I write, a fifth of S&P 500 components are up 9% or more so far this year.

And the difference between those two numbers should be sending you a very important message right now: stock picking still matters in this market.

To figure out which stocks look primed to outperform as we charge deeper into February, we're turning to the charts for a technical look at five large-cap breakout trades to buy - and when you should buy them.

First, a quick note on the technical toolbox we're using here: technical analysis is a study of the market itself. Since the market is ultimately the only mechanism that determines a stock's price, technical analysis is a valuable tool even in the roughest of trading conditions. Technical charts are used every day by proprietary trading floors, Wall Street's biggest financial firms, and individual investors to get an edge on the market. And research shows that skilled technical traders can bank gains as much as 90% of the time.

Every week, I take an in-depth look at big names that are telling important technical stories. Here's this week's look at five big stocks to trade.

Marriott International 

Leading things off is $34 billion hotelier Marriott International  (MAR - Get Report) . Marriott has enjoyed some seriously positive price trajectory lately - shares are almost 20% higher than they started six months ago, leaving the S&P 500 in its dust. Don't worry if you've missed out on that bullish move in Marriott, though. Shares of this hotel stock are testing a breakout towards a second leg higher this week.

Marriott has spent the last month and change forming an ascending triangle pattern, a bullish continuation pattern that's formed by horizontal resistance up above shares at $86, and uptrending support to the downside. Basically, as shares have bounced in between that pair of technically important price levels, this stock has been getting squeezed closer and closer to a breakout through that aforementioned price ceiling at $86. Shares ended yesterday slightly above that line in the sand, but we'll need to see some continuation in today's session to call the breakout "confirmed".

Meanwhile, we're getting an additional glimpse at Marriott's upside power through its relative strength, the indicator down at the bottom of the chart. Relative strength shows MAR's price performance relative to the rest of the stock market - the fact that it's holding onto higher lows indicates that shares are continuing to beat Mr. Market, even now. Once the $86 breakout gets confirmed, it makes sense to pull the trigger on this trade with a stop at the 50-day moving average.

Canadian Pacific Railway 

Canadian Pacific Railway  (CP - Get Report) is showing traders the exact same price pattern right now - albeit in the longer-term. Like Marriott, Canadian Pacific has spent the last several months consolidating in an ascending triangle. For this $21 billion railroad operator, the breakout level to watch is resistance up at $155.

What makes that $155 level so important for this stock? It all boils down to buyers and sellers. Price patterns, like this ascending triangle setup, are a good quick way to identify what's going on in the price action, but they're not the ultimate reason shares look attractive here. Instead, the "why" is driven by basic supply and demand for Canadian Pacific's shares themselves.

The $155 resistance level is a price where there has been an excess of supply of shares; in other words, it's a spot where sellers have previously been more eager to step in and take gains than buyers have been to buy. That's what makes a breakout above $155 so significant - the move means that buyers are finally strong enough to absorb all of the excess supply above that price level.

Vodafone Group

Things haven't looked so hot of late for shares of $65 billion UK-based telecom stock Vodafone Group (VOD) . Instead, shares have slid almost 30% lower since peaking back in late May, underperforming the major market averages by a big margin. That's the bad news. The good news is that Vodafone is finally looking "bottomy" this winter.

Vodafone has spent the last few months carving out a double bottom, a bullish reversal setup that looks just like it sounds. The double bottom in Vodafone is formed by a pair of swing lows that bottomed out around the $24 price level, separated by a peak up at $26.50. A breakout above that $26.50 high is the signal that buyers have taken back control of this big Eurozone stock.

Price momentum, measured by 14-day RSI, is the side-indicator to look at in VOD. Our momentum gauge has made a series of higher lows during this stock's reversal pattern, a bullish divergence that indicates buyers are stepping back in behind the scenes. Still, price is primary - wait for VOD to push through $26.50 before you buy it.

PayPal Holdings 

You don't have to know much about trading to decipher the chart of $50 billion payments stock PayPal Holdings (PYPL - Get Report) . Instead, the price action that's been in play for the better part of the last year is about as simple as they can get. PayPal has been in an uptrend since the beginning of 2016, climbing about 25% higher along the way - and it's still a "buy the dips stock" this winter.

PayPal's uptrend is formed by a pair of parallel trendlines that have corralled most of this stock's price action stretching back to last February. So far, every test of the bottom of the channel at trendline support has provided investors with a low-risk buying opportunity before PYPL's next up-leg. And shares are bouncing off of support for a sixth time this week.

Actually waiting for that bounce is important for two key reasons: it's the spot where shares have the most room to move up before they hit resistance, and it's the spot where the risk is the least (because shares have the least room to move lower before the channel breaks, invalidating the upside trade). Remember, all trend lines do eventually break, but by actually waiting for the bounce to happen first, you're ensuring PayPal can actually still catch a bid along that line before you put your money on shares.

WEC Energy Group 

Last on our list of potential breakout trades is $18.5 billion electric utility WEC Energy Group  (WEC - Get Report) . WEC has been a laggard in the last six months, dropping about 6.5% at the same time the S&P 500 was undergoing a major rally. But that under-performance could be about to turn around in a big way in 2017: WEC is looking "bottomy" in the long-term here.

WEC is forming a textbook example of an inverse head and shoulders pattern, a bullish reversal setup that signals exhaustion among sellers. The pattern is formed by two swing lows that bottom out at approximately the same level (the shoulders), separated by a lower low (the head). The buy signal gets triggered on a move through WEC's neckline, currently just below $60.

It's no coincidence that a breakout from the inverse head and shoulders pattern in WEC coincides with a breakout through the downtrend resistance line that's acted like a sliding ceiling for shares since they peaked back in the summer. That "double signal" adds extra confirmation that a push through $60 is likely to be followed up by some prolonged upside as the trend fully reverses higher in WEC. Keep an eye on how shares trade in the sessions ahead -- this big utility stock is very close to breakout territory.

At the time of publication, author had no positions in the stocks mentioned.