Most stock investors lose money because they invest in companies that seem good at a particular point in time, but are lacking the fundamentals of a long-lasting stable company.

The high CAGR in the early years of the investing period, due to buying at a discount, tended to decline and approach that of the intrinsic EPS GR of the companies over a longer investment time-frame.

Chapter 20 - “Margin of Safety” as the Central Concept of Investment

A single quote by Graham on page 516 struck me:

Observation over many years has taught us that the chief losses to investors come from the purchase of low-quality securities at times of favorable business conditions.

Basically, Graham is saying that most stock investors lose money because they invest in companies that seem good at a particular point in time, but are lacking the fundamentals of a long-lasting stable company.

This seems obvious on the surface, but it’s actually a great argument for thinking more carefully about your individual stock investments. If most of your losses come from buying companies that seem healthy but really aren’t, isn’t that a profound argument for carefully studying any company you might invest in?