The S&P 500 is almost exactly where it was one year ago. But fortunately, it took a bumpy path to get back to this point. Corrections in August and January, and milder but significant selloffs in September, November and February, created ample buying opportunities for attractive stocks — and we were happy to take advantage.

Let’s take a look at some of our winners to see whether they remain worthwhile buy candidates, or if holding or taking profits makes more sense.

#-ad_banner-#​Arotech (Nasdaq: ARTX) is up about 50% since I recommended it on Dec. 17. The specialty defense contractor makes simulators, trainers and high-performance batteries for aviation and marine use. Its customers include U.S. and foreign military and homeland security forces.

As I wrote in December, the U.S. defense budget is on the rise, thanks to a rare bipartisan agreement between Congress and the White House that loosened the purse strings after a few years of austerity. Arotech’s innovative products are on the shopping lists of every military procurement strategist, as they provide next-generation capabilities of use in modern conflicts. For example, Arotech is the supplier for the U.S. Army’s SWIPES program (Soldier Worn Integrated Power Equipment Systems), which give each soldier an extremely lightweight portable power system that continuously charges the batteries in a soldier’s radio, GPS unit, shot-detection units and other electronic devices. Arotech also provides lightweight portable solar panels for field operations. And the company is the leading provider of weapons simulators used in air combat training (and for civilian vehicle safety training).

A fast sales and earnings grower with a solid balance sheet, strong products, established relationships with major customers around the globe and the budgetary wind at its back, Arotech looks like a good candidate to re-test its 52-week high of $4.13 in the 12 months. Hold it if you own it, and buy it if you don’t — with the caveat that as a low-priced stock, it can be quite volatile.

Mitek Systems (Nasdaq: MITK) has gained about 22% since I recommended the stock on April 18. The global leader in identity verification for mobile transactions, Mitek is in the sweet spot of a fast-growing industry. Every day, tens of millions of people use a mobile device to make a credit-card payment, open an account or get an insurance quote, identity verification comes into play. Mitek provides that service to more than 4,500 organizations’ apps, and growing, with a focus on financial-services providers and a growing presence among online retailers and pharmacies. ​

As I wrote in April, online fraud is a major concern for all sorts of companies, and consumers are increasingly sensitive to the likelihood of account takeover and new account fraud. The amount of money involved in such fraud will rise from $5 billion in 2015 to $8 billion in 2018, according to Javelin Strategy & Research, as more transactions move online and fraud perpetrators up their games. Mitek is taking advantage of this demand, and its earnings are expected to grow at a blistering 25% annualized rate in the coming years. The company has no debt, generates strong cash flow and seems to have excellent technology. It’s a tad expensive at the current price, so wait for dips below $6.75 to add to your position. But this one remains a long-term winner.

Proofpoint (Nasdaq: PFPT) is up about 19% since I recommended it on March 21. The fast-growing cybersecurity provider is a leading provider of “security as a service” products that protect messages, social media and data for enterprises and consumers. Clients include half of the Fortune 500 and many of the largest U.S. banks, retailers and pharmaceutical companies. The company’s next-generation email security solutions effectively use encryption and other secure storage technologies to fight phishing, fraud and other outside attacks — a huge and growing threat. Another specialty is helping companies archive and protect all of the data they need to keep to comply with regulations and customer needs — a market growing at a double-digit annualized rate.

The company operates in a highly competitive market led by Symantec, yet the fast-rising tide is lifting all boats. Proofpoint is growing about revenue by about 35% a year and remains on track to become profitable this year. However, it’s too pricey at current levels to buy now. I’d consider picking up shares if the stock price dips below $58, and hold otherwise.

In the same article, I recommended Zendesk (NYSE: ZEN), which is up 36% since then. The company makes easy-to-use customer service interfaces for companies to manage one-on-one interactions, help answer questions in various ways (including online chats) and gather data from customers. Its revenue is soaring and earnings losses are shrinking faster than expected. But given its sharp runup in recent weeks and a sky-high valuation, I’d take profits on this lucrative three-month trade and use the profits on a less expensive stock. That said, the company seems to be hitting on all cylinders. If its share price drops, we’ll consider adding shares.

Risks To Consider: These are stocks of small to midsize companies in relatively undiversified business lines; their short-term results are vulnerable to unexpected downturns or other factors affecting their sectors. In addition, note that high-P/E stocks tend to drop sharply on bad news.
    
Action To Take: Buy Arotech below $3, Mitek Systems below $7 and Proofpoint below $58. Sell Zendesk.

Editor’s Note: If you’re looking for more big gains, this stock has turned every $1,000 invested back in 1972 into a stunning $2,669,645 today. But thanks to the actions of 40 members of Congress… it’s flashing “buy” right now. Click here to see why it could soar triple- digits over the next 12 months.