Looking into the current session, Duke Energy Inc. DUK is trading at $99.17, after a 1.05% drop. Over the past month, the stock fell by 3.20%, but over the past year, it actually went up by 5.65%. With questionable short-term performance like this, and great long-term performance, long-term shareholders might want to start looking into the company's price-to-earnings ratio.

Assuming that all other factors are held constant, this could present itself as an opportunity for shareholders trying to capitalize on the higher share price. The stock is currently under from its 52 week high by 8.50%.

The P/E ratio is used by long-term shareholders to assess the company's market performance against aggregate market data, historical earnings, and the industry at large. A lower P/E can either represent a company's poor future earnings potential or a buying opportunity relative to other stocks. It shows that shareholders are less than willing to pay a high share price, because they do not expect the company to exhibit growth, in terms of future earnings.

Depending on the particular phase of a business cycle, some industries will perform better than others.

Compared to the aggregate P/E ratio of 23.59 in the Electric Utilities industry, Duke Energy Inc. has a higher P/E ratio of 25.96. Shareholders might be inclined to think that Duke Energy Inc. might perform better than its industry group. It's also possible that the stock is overvalued.

P/E ratio is not always a great indicator of the company's performance. Depending on the earnings makeup of a company, investors can become unable to attain key insights from trailing earnings.