Right now, Regeneron Pharmaceuticals Inc. REGN share price is at $484.95, after a 0.15% gain. Moreover, over the past month, the stock fell by 3.99%, but in the past year, increased by 29.90%. Shareholders might be interested in knowing whether the stock is overvalued, even if the company is performing up to par in the current session. 

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 27.04%. 

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. 

Compared to the aggregate P/E ratio of the 35.98 in the Biotechnology industry, Regeneron Pharmaceuticals Inc. has a lower P/E ratio of 17.75. Shareholders might be inclined to think that the stock might perform worse than its industry peers. It’s also possible that the stock is undervalued. 

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.