The Ancient Greek philosophy of Stoicism has been around for more than 2300 years but is now more relevant than ever for investors. Those who want to build wealth in the stock market do well when they invest like a Stoic.

The core idea of Stoicism is simple: Focus on what you control and ignore everything else. But as investors, we tend to focus on the latter, which harms our future returns.

If you always focus on the factors you don’t control, like the state of the economy, inflation, or what the Fed does next, you will lose money. No one can predict macro factors or what the stock market does in the short term.

As investors, we should focus on what we control, and that’s a very limited area. Essentially, we only control our own decisions about what to invest in.

So, what would a Stoic invest in? Quality. As Seneca, one of the most famous Stoic philosophers, once said: