5 leçons tirées du livre de Benjamin Graham, « L'investisseur intelligent »

by | Aug 6, 2026

Why should you read Benjamin Graham’s The Intelligent Investor, the Definitive Book on Value Investing? Well, because here is what Warren Buffett said about it:

“I read the first edition of this book in early 1950, when I was 19. I thought then that it was, by far, the best book about investing ever written. I still think it is.”

Any book that gets THAT kind of a review from someone like Warren Buffett is one that is worth our time, I’d argue. And so, I re-read it, and though I’m a few years older than Buffett’s 19, I’d still agree with his assessment that it is indeed one of the best books about investing ever written.

The copy that I picked up was the revised edition, with a preface and appendix by Warren Buffett, and updated with new commentary by Jason Zweig. As the name suggests, this book hopes to teach the reader to be an intelligent investor. It won’t teach you how to beat the market, and if any book tells you how to do that, that’s the first red flag, because no one can teach you to consistently do that. However, this book helps a reader:

  1. Minimize the potential for large losses,
  2. Maximize the chances for big gains, and
  3. Control self defeating behaviour.

Graham shares the various lessons he learnt himself starting on Wall Street in 1914 – just before the devastating first World War, and well before the 1929 crash. Talk about baptism by fire!

The book is divided into 20 chapters, and the edition I read came with commentary on each. The chapters cover investment vs speculation (as relevant today as it was nearly 100 years ago!) portfolio theory, market fluctuations, stock selection, case studies, and others. Each of the chapters and commentaries are worth your while, but I’d like to share some key lessons I got from the book, and why I think they are important.

Lessons Learnt from The Intelligent Investor

1. Investment is not speculation: To my mind, this is the most important lesson of the book – and its in the very first chapter. According to Graham, “An investment operation is one which, upon thorough analysis, promises safety of principal and an adequate return. Operations not meeting these requirements are speculative.” Meme stocks? Speculative. Betting on a “sure thing” IPO? Speculative. If you analyze a company and its business, and deem it to be strong, and think it will keep your capital safe and produce returns and you buy its stock based on that, then you are an investor.

2. If you have a thesis in which you believe, then market fluctuations are an opportunity. According to Graham, there are two ways to benefit from market moves – timing and pricing. For timing, it means buying or holding when prices are expected to go up, and sell or refrain from buying when prices are expected to go down. For pricing, buy low and sell high. How to do it? That’s harder than you think. 

3. You have to build in a margin of safety. Warren Buffett says Chapter 20 is essential reading. This is the chapter on Margins of Safety. In it, Graham asks investors to focus on four principles:

a. Know your business,

b. Don’t let anyone else run your business unless you supervise them thoroughly, or trust them completely,

c. Keep away from ventures in which you have much to lose and little to gain, and

 d. Believe in yourself – specifically in your knowledge and expertise.

4. Know yourself. One thing that comes across clearly in the book is the behaviour matters a lot more than mathematics in investing. In fact, in nearly all of Zweig’s commentary, he focuses on behavioural aspects of investing. There is freedom in knowing that some of our irrational behaviour is because of how our brains are wired, and there is even more freedom in knowing tips to counter biases.

5. Diversification is critical. What if AI does not work out as expected? What if it does? What if oil and gas falls? What if banks rise? Diversification offers investors a chance to both minimize loss, and maximize the potential for gains.

Does The Intelligent Investor Work in 2026?

The Intelligent Investor first came out in 1949, which means that some of it is dated. I’d argue that a lot of it is still relevant. The best parts of the book are its behavioural tips and lessons, including the lessons I outlined. However, there are some critiques of the book that are fair.

  1. No Magic Bullet: The book does not offer investment tips, or stock ideas or even actual formulae to decide on what consists of value. It just suggests that the reader figure out what works best for them.
  2. Not All Cheap Stocks are Good: The book is based on value investing, which means investors should buy companies below their intrinsic value. This does not always mean that the underlying investment or business is a good one. It could also give some readers the idea that a micro cap company is a good buy, and this might not be the case.
  3. Passive Investments Work: For DIY investors who don’t have the time, skill, knowledge, inclination, or various combinations thereof, there are advantages of passive investing, through vehicles like exchange traded funds (ETFs.). The book was written before ETFs became a thing, and so it naturally does not address this important vehicle for investors. And it certainly does not mention covered call ETFs, which aim to generate income for investors through owning a portfolio of stocks and then selling call options on those stocks to help generate income paid to investors. You can find out more about covered calls ici. Harvest Portfolios has a wide range of covered call ETFs for investors of all stripes.

This is a good book for investors to read. And if you do read it lend an eye to the era in which it was written. There is a lot to be gained from it!

Some Other Things I Did in July

  • FIFA World Cup in Toronto  – Unfortunately, I was not able to get tickets to the games in Toronto’s BMO Stadium, but I did attend the Fan Fest and I had an incredible time! The energy, the food, the vibes, were all great!
  • Medusa – A modern retelling of the ancient story – it was an intense experience!
  • Pho Ngoc Yen – The braised beef short rib pho was sheer poetry!
Clause de non-responsabilité

The opinions and views expressed in this book are those of the author and do not necessarily reflect the views of Harvest ETFs. Similarly, the opinions and views expressed in this review are solely those of the reviewer (the Author) and do not represent the views of Harvest ETFs. The Author and Harvest ETFs have no affiliation with the author of the book.

Investment decisions should be made in consultation with a licensed and experienced investment professional. This review is provided for educational purposes only and should not be interpreted as investment advice.

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