Looking into the current session, Corning Inc. GLW is trading at $36.31, after a 0.1% decrease. Over the past month, the stock fell by 2.13%, but over the past year, it actually increased by 26.09%. 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 below from its 52 week high by 5.53%. 

The P/E ratio measures the current share price to the company's earnings per share. It is used by long-term investors to analyze the company’s current performance against its past earnings, historical data and aggregate market data for the industry or the indices, such as S&P 500. A higher P/E indicates that investors expect the company to perform better in the future, and the stock is probably overvalued, but not necessarily. It also shows that investors are willing to pay a higher share price currently, because they expect the company to perform better in the upcoming quarters. This leads investors to also remain optimistic about rising dividends in the future. 

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

Compared to the aggregate P/E ratio of 86.89 in the Electronic Equipment, Instruments & Components industry, Corning Inc. has a higher P/E ratio of 139.81. Shareholders might be inclined to think that Corning Inc. might perform better than its industry group. It’s also possible that the stock is overvalued. 

There are many limitations to price to earnings ratio. It is sometimes difficult to determine the nature of the earnings makeup of a company. Shareholders might not get what they're looking for, from trailing earnings.