PER: The Metric That Can Never Be Missing in Your Investment Analysis

When we delve into the world of stock market investing, there is a fundamental question every analyst must ask: Is this company truly valued correctly? The answer often lies in a specific metric that has endured for decades in financial markets. In this analysis, we will uncover the secrets of this indicator, its practical usefulness, and how to apply it correctly to make more informed investment decisions.

Understanding the Fundamental Metric: What Is the PER Really

The PER, whose full name is Price/Earnings Ratio, functions as a lens through which we can observe the relationship between what the market pays for a company and what that company generates as periodic earnings. Essentially, the PER reveals how many years of current (projected over 12 months) earnings would be needed to equal the total market value of the company.

If we say a company trades at a PER of 15, this means that 15 years of net earnings at the current level would be required for these earnings to match the company’s market value. This metric is among the six most critical ratios for evaluating corporate health, along with EPS (Earnings Per Share), Price/Book Value, EBITDA, ROE, and ROA.

How PER Translates in the Real Stock Market

The behavior of PER in real financial markets is varied and complex. Take, for example, the historical data of Meta Platforms: for years, the PER steadily decreased while the stock price increased. This indicated a business growing steadily, generating increasingly higher profits. However, starting from the last quarter of 2022, this pattern reversed. Despite PER ratios reaching historic lows, the stock price continued to fall. The reason? Restrictive monetary policies implemented by central banks, which especially impacted tech valuations regardless of operational performance.

Another instructive case is Boeing. In this company, we observe how the PER remains within a relatively stable range, oscillating between positive and negative values depending on the period, while the stock moves up and down in direct correlation. This example is particularly revealing because it shows that the metric does not always explain the price movement: external factors such as regulatory changes or geopolitical events play decisive roles.

The Math Behind the Indicator: Two Ways to Calculate

The calculation of PER admits two equivalent approaches that yield the same result:

First method (using global magnitudes):