Sadly, there's no such thing as an ultimate buy signal when it comes to investing in stocks. Identifying companies with the wind at their backs takes time, patience, and a good dose of due diligence.

There is, however, an easy way to increase your odds of finding the stocks that will beat the market. At Motley Fool CAPS, the Fool's investing community of more than 135,000 members, we've found that our "five-star portfolio" is up 15.31% between January 2007 and April 2009, compared to a loss of 40.6% for the S&P 500.

To fully capture the upside potential of those highly rated stocks, it makes sense to identify them just as soon as they are upgraded to four- and five-star status. Fortunately, our CAPS screener now makes it possible to do this. Below, for example, is a list of companies that have been upgraded to four-star status from three stars just yesterday. These stock ideas are only a starting point, of course. Be sure to join us on CAPS to dig in even further.

Company

All-Stars Saying Outperform

iShares Dow Jones US Oil Equip. (ETF) (NYSE:IEZ)

142 of 147

Danaher Corp (NYSE:DHR)

383 of 405

Nalco Holding Company (NYSE:NLC)

120 of 127

Columbia Sportswear Company (NASDAQ:COLM)

537 of 589

EOG Resources, Inc. (NYSE:EOG)

640 of 665

Airvana, Inc.(OTC BB: AIRV)

122 of 135

Data from Motley Fool CAPS, July 8, 2009.

Come join us on CAPS, absolutely free, to learn more about these and countless other interesting stock ideas.