Neither U.S. economic data nor testimony from Federal Reserve Chairwoman Janet Yellen could save the S&P 500 (SNPINDEX:^GSPC) from ending in negative territory today.

The big economic report that weighed on the markets was the release of June's retail sales figures. With the absence of weather-related concerns, economists were looking for consumers to be out spending in force. Wall Street had been projecting that retail sales would expand 0.7%, but they actually expanded by just 0.2%, which was down notably from the 0.5% expansion reported for May. Although retail sales excluding autos were a bit better at 0.4% growth, this, too, fell short of estimates by 0.2%.

What this could signal is consumers' unwillingness to open their wallets because of economic uncertainty. Although consumer confidence figures would lead us to believe that consumers are feeling more confident about their financial future, what ultimately matters for U.S. GDP is whether they spend. As of now, it appears that retail spending growth could be in question.

In addition, Janet Yellen, while testifying before the Senate Banking Committee, commented that valuations in select sectors of the stock market are looking stretched, such as with social media and biotech stocks. That comment immediately sent ripples throughout both sectors and pushed a number of key companies in each industry lower.

By day's end, the S&P 500 had given up 3.82 points (-0.19%) to close at 1,973.28. All things considered, this can almost be viewed as a victory for the bulls, with the S&P 500 down nearly 12 points in midday trading. Despite the downdraft, three stocks managed to motor significantly higher.

Source: Plug Power.

Leading the charge to the upside is fuel-cell system developer Plug Power (NASDAQ:PLUG), which surged 16% after research firm FBR Capital initiated coverage on the company with an "outperform" rating. As the covering analyst at FBR noted, Plug Power's transition to offering complete hydrogen-based solutions, coupled with its landing sizable contracts in recent months, should allow it to land additional large-scale deals. While the analyst projects that the next 12 months will be the most crucial for Plug Power, there are a number of catalysts upcoming, including the launch of a new hydrogen delivery system, as well as the potential for expansion into overseas markets.

Plug Power has been lighting things up since it struck a deal with Wal-Mart to provide six of its U.S. Supercenters with 1,738 forklifts powered by its proprietary fuel cells. While this is certainly a great deal for Plug Power in terms of gaining brand-name recognition from this biggest retailer in the world, Plug Power will still need to demonstrate that it can garner new deals on a regular basis. With the company only projected to be marginally profitable at best, I'd consider it aggressively valued here, especially after today's move higher.

Also vaulting to the upside by 13% on the heels of analyst commentary was recent IPO GoPro (NASDAQ:GPRO). The maker of first-person point-of-view cameras jumped after research firm JMP Securities started the company with a "market perform" rating and gave it a $60 price target. Specifically, JMP anticipates that more consumers will soon own wearable cameras and that GoPro has yet to take advantage of a number of key opportunities, such as generating advertising revenue through its own social-media avenues.

Source: Gianfranco Blanco, Flickr.

However, it's also worth noting that JMP's price target implies a 63% gain in GoPro shares, yet the research firm only considers it to be a "market perform." Sometimes analyst ratings are just silly, and this appears to be one of those white noise-type moments. Generally speaking, analyst ratings should be ignored, as they rarely play a role in our long-term investing thesis. But one aspect that does make sense of JMP's research that I noted recently is GoPro's inability thus far to rely on social media to boost its business. At a valuation north of $5 billion, even with the euphoria surrounding the product, GoPro doesn't make a lot of sense as an investment. Until the company can successfully add new sources of revenue to complement its hardware, I'd suggest sticking firmly to the sidelines.

Source: Pinkyracer, Flickr.

Lastly, specialty chemicals producer Rockwood Holdings (UNKNOWN:ROC.DL) formed a chemical bond this morning with Albemarle (NYSE:ALB), after Albemarle agreed to buy Rockwood for $6.2 billion in a cash and stock deal. Under the terms of the deal, which sent Rockwood higher by 9.8% on the day, Rockwood shareholders will receive $50.65 in cash and 0.4803 shares of Albemarle for each share of Rockwood they currently own. When the deal was announced, it worked out to about a 13% premium from yesterday's close.

The reason for the deal is simple: lithium! Rockwood is currently the preeminent supplier of lithium, which is used in products like iPads and rechargeable batteries for electric vehicles. Albemarle, being one of the other four primary lithium suppliers, will look to secure the lion's share of lithium production and demand moving forward. Considering the growing demand for EVs, this looks like a genius move by Albemarle and a handsome premium for Rockwood's shareholders.