In the current session, ARCA biopharma Inc. ABIO is trading at $7.85, after a 98.73% spike. Over the past month, the stock increased by 114.48%, and in the past year, by 35.58%. 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 11.60%.

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 the 0.03 in the biotechnology industry, ARCA biopharma has a lower P/E ratio of 0.0. Shareholders might be inclined to think that they might perform worse than its industry peers. It’s also possible that the stock is undervalued.

There are many limitations to P/E 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.