In the current session, Apple Inc. AAPL is trading at $134.08, after a 0.3% gain. Over the past month, the stock increased by 9.05%, and in the past year, by 80.31%. With performance like this, long-term shareholders optimistic but others are more likely to look into the price-to-earnings ratio to see if the stock might be overvalued.

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 3.39%. 

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. 

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

Apple Inc. has a better P/E ratio of 40.77 than the aggregate P/E ratio of 24.06 of the Technology Hardware, Storage & Peripherals industry. Ideally, one might believe that Apple Inc. might perform better in the future than it’s industry group, but it’s probable 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.