Don't settle for ordinary quarterly reports.

I take a look at three companies that beat market expectations every week, since I believe that it's the biggest factor in a stock beating the market. Leaving Wall Street's pros with stunned expressions can be a good thing. It usually means that the companies have more in the tank than analysts figured. Capital appreciation typically follows.

Let's take a look at a few companies that humbled the prognosticators over the past few trading days.

We can start with Costco (Nasdaq: COST). The warehouse club's quarterly profit climbed 16% to $0.97 a share, just ahead of the $0.95 that analysts were targeting. The outperformance isn't exactly a trend. Rival BJ's Wholesale (NYSE: BJ) came up well short in its latest quarter.

Alcoa (NYSE: AA) didn't have to wait until tomorrow -- as its old slogan goes -- to come through for its investors. The aluminum giant posted net income of $0.09 a share after backing out one-time charges, nearly twice what Wall Street was expecting.

Alcoa ran into a rough patch during the heart of the recession, but it has now come through with profitable performances in each of the past five quarters.

Finally, we have Diamond Foods (Nasdaq: DMND) shining nicely. Unlike salty snack champ PepsiCo (NYSE: PEP) -- which merely met the market's bottom-line estimate last week -- Diamond's non-GAAP adjusted quarterly net income of $0.34 a share blew past what the pros were forecasting. The maker of Kettle potato chips, Emerald nuts, and Pop Secret microwaveable popcorn was only on the hook for earnings of $0.28 a share.

It's important to keep watching the companies that surpass expectations. Over time, it will be a lucrative experience for investors as the market rewards the overachievers. That's the kind of surprise that we look for in the Rule Breakers newsletter service. Want in? Check out a 30-day trial subscription.

Either way, come back next Monday to learn about more stocks that blew the market away.