Last Week's Biggest Stock Movers: Aruba, Weight Watchers

Low Fat Ice Cream   Low-Fat Ice Cream  Light choices products healthy treat Weight Watchers chocolate bar
Cassandra Hubbart/AOL

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.

Aruba Networks (ARUN) -- Up 35 percent last week

One of last week's biggest gainers was Aruba Networks. Strong earnings or buyout chatter can propel a stock higher, and Aruba Networks has a bit of both. The networking gear specialist did post better-than-expected quarterly results, but the big driver was a rumor that Hewlett-Packard (HPQ) was in talks to acquire the fast-growing tech upstart. HP would establish itself as a major player in Wi-Fi infrastructure with the potential purchase.

First Solar (FSLR) -- Up 22 percent last week

Things are heating up in solar. First Solar moved higher after the provider of photovoltaic solar systems announced plans to partner with SunPower (SPWR) to create an income-producing investment. SunPower and First Solar are in advanced talks to create a yield-generating stock that would own and operate solar power-backed projects. With investors chasing payouts in this low-interest-rate environment, it's a smart move.

Zagg (ZAGG) -- Up 18 percent last week

Zagg moved higher after offering up better-than-expected financials. The maker of smartphone and tablet accessories saw its sales for the holiday quarter soar 53 percent from the prior year's showing, fueled by a record number of screen protector and tablet keyboard sales.

Zagg's original smash hit was invisibleShield, the thin transparent film that can be placed over smartphone and tablet screens to protect them from getting scratched. Its quarterly profit of 43 cents a share was well ahead of the 9 cents a share that the pros were targeting.

Weight Watchers (WTW) -- Down 41 percent last week

It's not just Weight Watchers members losing weight these days. Investors have also slimmed down after another brutal quarterly report out of the dieting plan specialist. Weight Watchers has seen its number of active subscribers plunge 15 percent over the past year to 2.5 million. There are just too many free or cheaper alternatives to losing weight these days, and Weight Watchers is feeling the pinch.

Daktronics (DAKT) -- Down 19 percent last week

Those keeping score on Daktronics were burned last week after it posted disappointing quarterly results. The scoreboard maker posted flat sales growth, barely breaking even on the bottom line. Wall Street was holding out for a much larger profit. Daktronics has now fallen short in three of the past four quarters.

The more problematic aspect of Daktronics' report is that the number of orders signed during the period fell sharply, lowering its backlog of pending orders. This doesn't bode well for growth in the coming quarters.

Taser International (TASR) -- Down 15 percent last week

The stun-gun maker also slipped after falling short of analyst profit forecasts. Unlike Daktronics, this is a rare miss for Taser, which had beaten Wall Street income estimates with ease over the past several quarters.

Taser shares had moved higher in recent months after a couple of notorious and fatal police confrontations resulted in a spike in interest for less-than-lethal weaponry. Net sales did climb 17 percent to hit a new quarterly record, but coming up short in profitability did force investors to reconsider the inflated valuation.

Motley Fool contributor Rick Munarriz has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. 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.