Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

Instead of starting the year off with a bang, the S&P 500 (SNPINDEX:^GSPC) began with a whimper, as mixed economic data at home and abroad pushed the iconic index to its worst performance in weeks.

On the bright side, weekly initial jobless claims dipped by 2,000 to a seasonally adjusted 339,000. With the holiday season now in the rearview mirror, these wild fluctuations we've witnessed in initial jobless claims should calm down, and we could see a slow but steady decline in the unemployment rate in 2014.

Working against the S&P 500, however, was the ISM manufacturing Index, which delivered strong expansion with a reading of 57 in December, but pulled back modestly from the reading of 57.3 in November. Also, manufacturing data in China, arguably the world's most important economy, was weaker than expected. The China Federation of Logistics and Purchasing noted that its purchasing managers index fell to 51 in December from a prior reading of 51.4, pointing to a slowing manufacturing sector expansion. If China's growth slows down, then many multinational companies could find themselves struggling to meet their 2014 estimates.

By day's end, the S&P 500 shed 16.38 points (0.89%) to close at 1,831.98. It may have been an ugly day for the overall market, but it started off well for alternative energy companies, which dominated today's list of top performers.

Leading the charge high was fuel cell systems developer Plug Power (NASDAQ:PLUG) -- the company's share price skyrocketed 50.3% after it announced that it had met its projected fourth-quarter order targets, which totaled about $32 million. Plug Power didn't allude to any financial impact from these orders, choosing instead to save those for its actual fourth-quarter results, but did note it received repeat business from the likes of Wal-Mart, Kroger, Mercedes-Benz, and BMW. This is a big step toward Plug Power's long-term viability, but we need to see definitive improvements in Plug Power's bottom-line before I break out my pompons.

China-based photovoltaic module manufacturer Yingli Green Energy (NYSE:YGE) also jumped a whopping 24.4% after announcing a joint venture with Shouzhou Coal Power, a subsidiary of Datong Coal Mine Group. As noted in its press release, and by my Foolish colleague Travis Hoium, the two have partnered together previously on a 20 MW utility-scale project in the Shanxi Province, so collaborations shouldn't be anything new for these companies. With the Chinese government looking to bring 35 GW of solar power online by 2015, this joint venture can only be viewed as a positive for both companies.

Finally, solar company Hanwha SolarOne (NASDAQ:HQCL) gained 18.1% after announcing a deal to supply 11.5 MW of solar modules to Solar Belgium NV, also known as Ikaros Solar, for a solar park in the United Kingdom. Ikaros intends to begin construction of the solar park this month, and complete the connection of its solar grid in March 2014. Like Yingli and Datong, this collaboration between Hanwha SolarOne and Ikaros has been going on for some time. However, like Plug Power, I would need to see a serious decline in Hanwha's losses before I'd even remotely consider this a viable investment opportunity.