You've heard of the "January Effect," where investors sell stocks in December for tax reasons, only to buy them back in January causing their price to jump.

Yet what about other months? Retailers, for example, have some seasons that perform better than others, simply because of the nature of the business. Some stocks even do better in September. Whatever the reason, investing based solely on the calendar is certainly not a Foolish strategy.

Still, wouldn't it be great to know ahead of time which stocks performed best at what times?

On Motley Fool CAPS, more than 115,000 members have weighed in on more than 5,400 stocks, awarding five-star ratings to the companies that best command their confidence. We've paired their opinions with data going as far back as five years to see which stocks perform best in each month. The following five companies seem to do best in September:


Market Cap

Avg. % Return-Sept

Avg. % Return-Rest of Year

CAPS Rating (out of 5 max)

YTD Return

Schiff Nutrition (NYSE:WNI)

$188.1 million





Comtech Telecommunications (NASDAQ:CMTL)

$1.2 billion






$128.3 million






$215.1 million





Aladdin Knowledge Systems (NASDAQ:ALDN)

$181.3 million





Sources: America Online, Motley Fool CAPS.

What's driven the outsized September performance of the Schiff Nutrition while the rest of the year is essentially flat? It's a tricky question, and one reason why we don't recommend using this as simply a list of stocks to buy or sell -- just a platform for further research. We need to look closer for the reason, but its four-star CAPS rating suggests investors think it may be worth a look.

If September really is their month to school the market, let's see which of the companies above might live up to that promise.

Attention, class!
As a surgical procedure, cardiac bypass surgery actually has a greater risk of death than either angioplasty or inserting a stent into the arteries. However, a major study shows that bypass surgery may actually have longer-lasting benefits for the patient.

That itself may translate into benefits for surgical device maker Cardica, whose PAS-Port system just received FDA approval. It also makes the C-Port Flex A, which can be used for closed-chest coronary artery bypass graft surgery with the daVinci robot, a minimally invasive surgery device by Intuitive Surgical (NASDAQ:ISRG). As CAPS member makerta says, FDA approval is a new chapter for Cardica: "PAS-Port approval starts a new phase of growth for this company."

Keeping fruits and vegetables fresh longer is the substance behind Landec's proprietary Breathway technology. Yet it also has a deal with Monsanto (NYSE:MON) for seed coatings, and with agriculture remaining a hot sector, this could translate into a much larger piece of business. Moreover, Landec landed the rights to sell Monsanto seeds in certain applications this fall.

Extending the shelf life of produce that is growing ever more expensive is behind CAPS member smisra2 thinking that Landec will outperform the market: "with rising prices, America will start to realize the amount of food they waste and look for ways to extend the life of food product. landec products will come in handy then." With strong results, a clean balance sheet, and a long time horizon, this Motley Fool Hidden Gems recommendation could have more shelf life than the produce it seeks to protect.

A calming effect
It pays to start your own research on these stocks on Motley Fool CAPS. Read a company's financial reports, scrutinize key data and charts, and examine the comments your fellow investors have made -- all from a stock's CAPS page. Your voice affects these stocks, whatever month the calendar may display. Since it's free to sign up and express your investing opinions, why not use this opportunity to take your star turn?

Landec is a Motley Fool Hidden Gems pick. Intuitive Surgical is a Rule Breakers recommendation. Try any of our Foolish newsletters today, free for 30 days.

Fool contributor Rich Duprey does not have a financial position in any of the stocks mentioned in this article. You can see his holdings here. The Motley Fool has a disclosure policy.