Right now, Sempra Energy Inc. SRE share price is at $135.43, after a 0.09% decrease. Over the past month, the stock increased by 4.43%, but over the past year, it actually fell by 8.41%. 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. 

The stock is currently above from its 52 week low by 53.90%. Assuming that all other factors are held constant, this could present itself as an opportunity for investors trying to diversify their portfolio with Multi-Utilities stocks, and capitalize on the lower share price observed over the year. 

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 indicates that shareholders do not expect the stock to perform better in the future, and that the company is probably undervalued. 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. 

Most often, an industry will prevail in a particular phase of a business cycle, than other industries. 

Sempra Energy Inc. has a lower P/E than the aggregate P/E of 21.24 of the Multi-Utilities industry. Ideally, one might believe that the stock might perform worse than its peers, but it’s also probable that the stock is undervalued. 

Price to earnings 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.