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

Grupo Aeroportuario del Centro Norte(ADR) (NASDAQ:OMAB)

219 of 229

iShares FTSE/Xinhua China 25 Index (ETF) (NYSE:FXI)

1530 of 1640

AB Volvo (ADR)(OTC BB: VOLVY)

189 of 203

Comverge, Inc.(OTC BB: COMV)

162 of 176

Lloyds TSB Group plc (ADR) (NYSE:LYG)

698 of 752

Data from Motley Fool CAPS, June 18, 2009.

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