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 back 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 with a loss of 40.6% for the S&P 500.

In order to fully capture the upside potential of those five-star stocks, it makes sense to identify them just as soon as they achieve 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 five-star status from four 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

Calgon Carbon (NYSE:CCC)

272 of 291

Vanguard Health Care ETF (NYSE:VHT)

117 of 122

Advantage Oil and Gas (NYSE:AAV)

529 of 551

Techwell (NASDAQ:TWLL)

212 of 217

Market Vectors Steel (NYSE:SLX)

270 of 275

Data from Motley Fool CAPS, Aug. 18, 2009.

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