The major stock market indices continue to push up against new highs, but investors shouldn’t be fooled.

Not every stock is moving higher in 2014, and some of the riskiest investments have cratered despite the S&P 500 being in the green for the year-to-date.

Investors have been lulled into a false sense of security after a roaring run last year that delivered tremendous profits via risky momentum stocks. But as the market gets selective, it’s more important than ever to make sure you’re not holding bubble stocks in your portfolio just because they’re fashionable names.

After all, fad stocks are nice when you’re riding the uptrend … but can be awfully painful when the bubble bursts.

To keep you safe across the rest of the year and beyond, here are five fashionable investments that are starting to lose steam and should be sold ASAP.

Fad Investments #1: Big Data

It’s undeniable that the digital age as ushered in a whole new way of looking at the numbers. After all, there are all those hyped-up headlines about how 90% of the world’s data has been created in the last two years.

Investors have bought into this narrative by buying big data stocks like Splunk (SPLK), which went public in 2012, doubled in 2013.

Of course, that was 2013. This year, big data stocks have taken a tumble; Splunk is down 23% in the last 30 days and newly public big data firm Tableau (DATA) is down by even more.

Why? Well, because these stocks have a very sexy growth story … but the profits are meager in the case of Tableau and non-existent in the case of Splunk.

Besides, as the old saying goes, “not everything that counts can be counted.” Businesses seem enamored with the idea of data for marketing and efficiencies, but in the end the numbers can only do so much for them.

Perhaps big data isn’t as indispensable as some spreadsheet lovers would like us to believe.

Fad Investments #2: Fuel-Cell Stocks

In 2013, electric-vehicle manufacturer Tesla (TSLA) more than quadrupled, captivating Wall Street. However, it’s a bit naïve to think off that any old company with a footprint in the electric vehicle space will be a big success just because TSLA stock took off.

That’s why investors who have piled into fuel-cell stocks should start reconsidering.

Fuel cell players like Plug Power (PLUG) and Ballard Power Systems (BLDP) soared to start the year; PLUG soared more than 1,000% from December 2013 to March 2014, and Ballard gained more than 500% in the same period.

They posted that kind of performance despite both companies bleeding cash, with no clear demand or growth for their product lines … just a nice narrative to keep selling to investors.

No wonder Citron Research released a note calling Plug Power a “casino stock” with “a history of broken promises and a failure to deliver.”

Shares of PLUG have dropped about 50% from their 52-week, and it could get even worse before it gets better for fuel cell stocks.

Fad Investments #3: Unprofitable Cloud Computing Stocks

While “the cloud” is all the rage, the recent S-1 from Box Inc. just about sums up what it’s like to be a small-time, cloud-computing software company in 2014.

“We have a history of cumulative losses, and we do not expect to be profitable for the foreseeable future. We have incurred significant losses in each period since our inception in 2005.”

What’s not to like?

Wall Street is salivating over companies like Box and it’s already-public brethren Workday (WDAY) and Netsuite (N) … and on some level, enthusiasm is warranted. Research firm IHS recently estimated cloud-related business spending will hit $235 billion by 2017 — up 60% double from 2013’s tally of $145 billion — and even a modest piece of that market can add up to big revenue potential

But let’s not forget that big tech players like Oracle (ORCL) may not have been as agile and responsive to the cloud trend, but are coming on strong. And even if smaller cloud players are seeing revenue growth, many are deeply unprofitable and can’t sustain current valuations forever without the hope of real profitability.

Maybe that’s why WDAY stock is down about 35% from its 52-week high at the end of February, as is NetSuite.

Tread very lightly in these smaller cloud players … because the pain may have just begun.

Fad Investments #4: 3D Printing Stocks

3D printers became the “next big thing” for investors last year. From April 2013 to January 2014, 3D Systems (DDD) tripled and Stratasys (SSYS) roughly doubled. Also, just last November, 3D printer Voxeljet (VJET) held a massively successful IPO.

And why not? On-demand printing via cheap, automated labor seems like a godsend for manufacturers … and all those stories of cheap, 3D printed prosthetics helping people around the world are simply amazing.

But here’s the thing: Those dreams don’t meet with the reality of 3D printing at all. The machines themselves remain pretty expensive, the blueprints and materials are still a bit unreliable, the actual process of printing a complex part can take hours, and a complex finished product could take days.

The expectations were big but the realities have been pretty bleak, so VJET, DDD and SSYS are all off between 30% and 60% in 2014 as a result.

So much for the 3D-printing revolution. Time to get real about things, and give up on these fad stocks.

Fad Investments #5: Microcap Marijuana Stocks

Sure, public opinion polls have shifted sharply in favor of legalizing marijuana use. And, yes, Colorado and Washington have already legalized pot, and many other states are pushing for some form of decriminalization.

But just because the business of marijuana is now moving into the mainstream, that doesn’t mean that these businesses will succeed — or that they will be good investments.

Consider the fact that many banks are reluctant to provide financing and support to marijuana businesses because of the risks and stigma of the industry.

Of course, that hasn’t stopped investors from piling into unprofitable micro-cap marijuana stocks with almost zero revenue.

To add insult to injury, these picks are easily manipulated, thanks to their low volume and stock prices of only a few pennies per share.

I won’t name names because I refuse to give any of these risky marijuana penny stocks any more ink than they have already gotten in the financial media lately … but the fact that some of these stocks are down as much as 60% since their February highs shows just how quickly this “next big thing” is burning out.

Time will tell whether there can be a viable marijuana industry in the U.S. But it is highly unlikely that micro-cap penny stocks languishing on the pink sheets are going to be the companies that emerge as the market leaders in the years to come.

Jeff Reeves is the editor of InvestorPlace.com and the author of The Frugal Investor’s Guide to Finding Great Stocks. As of this writing, he did not hold a position in any of the aforementioned securities. Write him at editor@investorplace.com or follow him on Twitter via @JeffReevesIP.