Have you ever heard people talking about EPS and wondered what it really is? I often come across this term in the stock market. Some say that a high EPS is better, while others say you need to look at EPS to find outstanding stocks. But if you don't truly understand it, it’s just a vague sound. So I studied this topic to get a clearer picture.

Simply put, EPS stands for Earnings Per Share. It is a financial ratio that compares a company's net profit (after expenses and taxes) to the number of shares issued by the company. In this sense, EPS indicates how much profit each share earns.

For example, if Company AA has a net profit of 1 million baht and has issued 1,000 shares, the EPS is 1,000 baht per share. But if Company BB has the same net profit but has issued 2,000 shares, the EPS would be 500 baht per share. From this example, you can see that EPS is a useful indicator for comparing different companies.

The calculation method is straightforward: divide net profit by the number of shares outstanding. However, in practice, companies use the weighted average number of shares throughout the year because the number of shares can change over time. A real example is PTT in 2025, which had a net profit of 90,166.37 million baht and 28,562,996,390.9774 shares outstanding. The EPS calculated is 3.57 baht per share.

Now, you might wonder: why is EPS used? Investors use EPS to analyze how efficiently a company generates profit. You compare a company's EPS with others in the same industry or compare the same company's EPS over different years to observe trends.

There are many other indicators derived from EPS, such as the PE Ratio (Price to Earnings Ratio), which divides the stock price by EPS to see how many years it would take to recover the investment. A low PE ratio suggests the stock might be undervalued.

Another is EPS Growth, which looks at the growth of earnings per share from this year to next year. A high EPS growth indicates good growth, which most investors favor.

But be cautious: EPS doesn't tell the whole story. It doesn't account for risk, future prospects, and can be artificially inflated through stock buybacks, which may not be a good sign. Therefore, EPS should be used together with other metrics like net profit, market value, return rate, and more.

There are also Basic EPS, Diluted EPS, and Adjusted EPS. Basic EPS is the fundamental measure, Diluted EPS considers potential additional shares from options or convertible securities, and Adjusted EPS adjusts for extraordinary items or environmental factors.

In summary, a good EPS isn't just a high number. You need to see where it comes from, how it grows, and compare it with other companies. Smart investing involves looking at the overall picture, not just a single indicator.