Investing isn't easy. Even Warren Buffett counsels that most investors should invest in a low-cost index like the S&P 500. That way, "you'll be buying into a wonderful industry, which in effect is all of American industry," he says.

But there are, of course, companies whose long-term fortunes differ substantially from the index. In this series, we look at how individual stocks have performed against the broad S&P 500. 

Step on up, PPL (NYSE: PPL).                                                                 

PPL shares have modestly outperformed the S&P 500 over the past quarter-century:

Ppl

Source: S&P Capital IQ.

Since 1987, shares have returned an average of 10.2% a year, compared with 9.7% a year for the S&P (both include dividends). That difference adds up fast. One thousand dollars invested in the S&P in 1987 would be worth $19,200 today. In PPL, it'd be worth $22,600.

Dividends accounted for a lot of those gains. Compounded since 1987, dividends have made up about 80% of PPL's total returns. For the S&P, dividends account for 39% of total returns.

Now have a look at how PPL earnings compare with S&P 500 earnings:

Ppl

Source: S&P Capital IQ.

Pretty average here. Since 1995, PPL earnings per share have increased by an average of 5.8% a year, compared with 6% a year for the broader index. 

What's that meant for valuations? PPL has traded for an average of 14 times earnings since 1987 -- below the 24 times earnings of the broader S&P 500.

Through it all, shares have been strong performers over the past quarter-century.  

Of course, the important question is whether that will continue. That's where you come in. Our CAPS community currently ranks PPL with a five-star rating (out of five). Care to disagree? Leave your thoughts in the comment section below, or add PPL to My Watchlist.