In the current session, Apple Inc. AAPL is trading at $406.66, after a 5.69% gain. Over the past month, the stock increased by 8.79%, and in the past year, by 110.36%. 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 above from its 52 week high by 1.71%.

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.

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

Apple Inc. has a better P/E ratio of 30.08 than the aggregate P/E ratio of 11.68 of the Consumer Electronics 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 may not be able to attain key insights from trailing earnings.