I recently listened to a podcast featuring Barry Ritholtz discussing his new book, How Not to Invest.
Ritholtz runs a U.S.-based wealth management firm that manages over $10 billion of private client money. What I respect about their business is that it wasn’t built by acquiring other advice businesses (we see a lot of that today locally). It grew organically — through blogging, newsletters, and sharing authentic ideas.
Ritholtz and his business partner, Josh Brown, met in 2004. They both love markets and writing. They committed to writing a blog every day, and over the past two decades, that consistency and the trust they built with readers helped them grow a thriving firm managing billions.
I first heard Ritholtz on a podcast back in 2018, talking about how publishing and writing built his business. That idea stuck with me — it’s one of the reasons I started writing these newsletters and contributing to platforms like Moneyweb.
His new book is packed with useful insights. Given how central writing has been to his business success, it’s worth paying attention. Here are some of the key takeaways :
The Amateur’s Advantage
Instead of giving us secrets to market success, the book focuses on what not to do — because most investors don’t fail from picking the wrong stock, but from repeating the same behavioural mistakes over and over again.
Ritholtz draws from Charley Ellis’s idea that amateurs win tennis matches not by hitting winners, but by making fewer mistakes than their opponents. The same applies to investing.
Avoid the big errors:
- Don’t overtrade.
- Don’t use leverage you don’t fully understand.
- Don’t get swept up in hype or narratives.
- Don’t follow people who got lucky once and now claim to see the future.
The Three Categories of Bad Ideas
Most bad investing outcomes fall into three categories:
- Bad ideas and how they spread — meme stocks, crypto hype, “guaranteed” returns.
- Basic maths misunderstandings — like underestimating compounding or thinking you can time the market.
- Self-destructive investor behaviour — overconfidence, panic selling, chasing performance.
The point he makes is that the real focus should be on how not to behave. If you can simply avoid making big mistakes, the long-term market averages will likely take care of the rest.
Watch Out for the “Halo Effect”
One of the more interesting themes is what he calls the halo effect: just because someone made money in one domain doesn’t mean they know anything about investing.
He points to examples like:
- Robert Kiyosaki, author of Rich Dad Poor Dad, calling for market crashes for over a decade.
- Michael Burry, who made one big call in the housing crisis and got a film made after him – The Big Short – but hasn’t exactly been consistent since.
I’ve written about these guys before.
The key question: Is this person actually qualified to be giving investment advice?
So, What Do You Do Instead?
- Stay humble.
- Accept that randomness plays a much bigger role than we’d like to admit.
- Reward process, not confidence.
- Avoid big mistakes.
- Don’t expect certainty from people who don’t know you — or your goals.
Ritholtz ends with a simple line:
“Make fewer mistakes. Keep more money.”
In his experience, that’s the real edge.
