Last Week's Biggest Stock Movers: Taser, American Airlines

Plenty of stocks go up and down in any given week. The gainers inspire us to keep investing. The decliners keep greed in check while reminding us about the risks of the equity markets.

Let's go over some of last week's best and worst performers.

Veeva Systems (VEEV) -- Up 17 percent last week

Shares of Veeva Systems soared after posting better than expected financial results. The provider of enterprise software solutions for pharmaceutical companies and emerging biotechs saw its revenue climb 52 percent for the quarter over the past year. Profitability grew even faster. As a cherry on top, Veeva's guidance is also nicely ahead of analyst forecasts.

American Airlines Group (AAL) -- Up 12 percent last week

Air carriers in general moved higher last week as jet fuel prices continued to head lower. Oil prices hit a four-year low. That's great news for travelers planning their holiday getaways, but it's even better for the airlines that stand to benefit from lower fuel since it's a major variable cost component of their operations.

Taser Systems (TASR) -- Up 11 percent last week

The violent incident in Ferguson, Missouri, has stirred up a lot of controversy, but one thing that both sides seem to agree on is that police officers can benefit from body cameras that provide an accurate depiction of what takes place in confrontations. Taser -- the company that's famous for its namesake stun guns -- also makes wearable cameras and runs the cloud-based Evidence.com platform that stores the recorded data.

Taser was already moving higher in light of the Ferguson incident, but the stock picked up some steam when the Winston-Salem, North Carolina, Police Department ordered 623 of TASER's Axon body cameras along with a five-year subscription to Evidence.com. The department made a smaller purchase of Axon cameras with a shorter Evidence.com subscription earlier this summer.

Goodrich Petroleum (GDP) -- Down 43 percent last week

The same plunge in oil prices that sent airlines higher naturally didn't go over so well with the companies exploring, developing and producing oil. Goodrich Petroleum was one of last week's biggest losers, shedding more than 43 percent of its value. The producer of oil and natural gas will be in for a world of hurt if oil prices remain low given its fixed extraction costs.

ReneSola (SOL) -- Down 17 percent last week

It wasn't just oil and gas taking a hit. Solar panel maker ReneSola slumped after posting weak quarterly results. The Chinese company experienced a 22 percent decline in shipments. There is a correlation between oil and solar energy. Interest in solar power spikes when fuel prices are on the rise. However, ReneSola has been a laggard within its own industry. It hasn't posted an annual profit since 2010.

Daktronics (DAKT) -- Down 11 percent last week

Investors know the score when they buy into Daktronics, the world's largest supplier of high-end electronic scoreboards and displays. Shares of Daktronics got sacked after serving up a soft financial report. Quarterly revenue inched higher, but operational challenges resulted in profitability going the other way. Daktronics has now missed Wall Street's profit targets in three of the past four quarters.

Motley Fool contributor Rick Munarriz has no position in any stocks mentioned. The Motley Fool recommends Veeva Systems. Try any of our Foolish newsletter services free for 30 days. Check out our free report on one great stock to buy for 2015 and beyond.