Well, we knew the stock market's monster rally couldn't last forever. After seeing the Nasdaq rise an astonishing 33% between October and March, reality is settling in: The index has dropped 5% since then.

But where some may see frustration, others see opportunity. The beauty of investing is that when times are good, you can get excited about your swelling portfolio. When they're bad, you can get excited about killer investment opportunities.

Since this summer, I've publicly called out one company each month that I'd be putting my Roth IRA money behind. Though the timeline has been short, the results speak for themselves: The overall portfolio is up almost 18%, and it is beating the market by nearly 9 percentage points.

This month I'm looking for excellent companies that have been unfairly punished during the latest market swoon. My five candidates are all worthy of your consideration -- as is the special free report I'm offering at the end about the five stocks you must keep your eyes on this earnings season.

Westport Innovations (Nasdaq: WPRT)
This designer of natural gas engines has been hit particularly hard recently. Since hitting an all-time high of more than $50 per share in late March, the company's stock has fallen roughly 40%! It's worth investigating why such a fall happened.

For starters, if we zoom out more, we see that the company had been on quite a tear over the past year. It's still up more than 20%, even after the recent collapse. Part of the stock's recent troubles could simply be due to momentum investors cashing in their shares and locking in their gains.

More likely, however, is the fact that the market is starting to worry about competition. Westport doesn't manufacture its natural gas engines; it just designs them. If a competitor were to become fully integrated (designing and manufacturing its own engines), it could represent a real threat. Cummins made just such an announcement, but a closer look at the situation reveals that Westport really doesn't have anything to worry about -- for now.

Solazyme (Nasdaq: SZYM)
Like Westport, Solazyme has seen shares tumble more than 30% since the beginning of April. The cutting-edge biofuel company is able to produce oils for use as fuel, or as a cosmetic or nutritional additive.

It seems that investors are worried that the U.S. Navy, a major customer of the company's biofuel, might not be willing to continue paying for it, as it costs around four times what regular fuel would cost them. This is especially worrisome since the country has become far less dependent on foreign oil in recent years.

I personally think the worries fail to take into consideration that the company is ramping up production -- which will bring the cost of the fuel down -- and that Solazyme has multiple revenue streams to draw from.

IPG Photonics (Nasdaq: IPGP)
This laser maker is down 37% since last July and 21% since mid-February. IPG has developed industrial strength fiber-optic lasers that are cheaper and more powerful than their carbon brethren. The company is also vertically integrated, producing everything from its own diodes to the end product.

While this integration is an enormous asset during boom times -- the company can get its own diodes for much cheaper than buying them from a vendor -- it can be a liability when economic uncertainty reigns. When orders for lasers fall, the company still has to pay employees working throughout the production line -- something it wouldn't have to do if it farmed out production for diodes.

So when investors are worried about the direction of the global manufacturing market -- as they seem to be today -- IPG suffers. But if you believe, as I do, that 10 years from now manufacturing will be doing better than it is today, IPG and its world-class lasers are an excellent buy.

A pair of printers
OK, I have a confession to make. I'm including two companies that haven't been beaten down lately. Both 3-D Systems (NYSE: DDD) and Stratasys (Nasdaq: SSYS) shareholders have enjoyed quite a ride. Shares for the two companies are up 96% and 64%, respectively, since the beginning of the year.

There are two crucial elements at play here: Both companies possess a technology that could revolutionize the way we live, and they're consolidating their power within the realm of 3-D printing. Even with their recent appreciation, shares at these prices could look cheap 10 years from now.

Which to choose?
You'll have to check back in next Monday to see which of these five companies I'll be putting my money behind. But they're all worthy of your consideration -- and I've backed that sentiment up with bullish CAPScalls for all of them on my All-Star profile.

In the meantime, we're right in the heart of earnings season. This is the time when great deals can be had. If you'd like to know where to look, check out our special free report before it's too late. Inside you'll get all the details on five companies our experts think you should be tuned into. But hurry, because some of them report this week! Get your copy today, absolutely free!