I just reread about Jim Simons and am truly impressed by how he built a $28 billion fortune. Not by talking or predicting the future, but through pure mathematics.

What’s remarkable about Jim Simons is that he doesn’t believe in what most investors trust. Instead of chasing traditional financial indicators, he and his team at Renaissance Technologies spent decades analyzing market data, searching for patterns that others completely overlook. These statistical anomalies are the key—they repeat over time, and once discovered, you can design algorithms to exploit them.

But what I find most fascinating is that Jim Simons doesn’t just look at long-term trends. He focuses on short-term price fluctuations, fleeting opportunities within small timeframes. Unlike traditional investors, his team can enter and exit positions very quickly, capturing profits regardless of the overall market direction.

There’s a strategy Jim Simons calls “Deja Vu”—basically, exploiting mean reversion. The idea is simple: asset prices tend to revert to their historical average. When prices deviate significantly from normal levels, models automatically buy undervalued assets and sell overvalued ones. This approach continuously generates profits by capitalizing on temporary mispricings.

Human resources are another factor. Jim Simons doesn’t hire finance experts. He recruits PhDs, data scientists, mathematicians, and physicists. Why? Because quantitative trading requires a completely different mindset. He even gives them equity in the company to keep them motivated to optimize the algorithms.

Regarding capital, Jim Simons employs a highly leveraged strategy—sometimes borrowing up to 17 dollars for every dollar invested. Now, this may sound risky, but Renaissance Technologies’ risk management systems are highly sophisticated. They not only amplify profits but also strategically control potential losses.

But perhaps the most crucial factor Jim Simons implemented is removing emotion from the equation. No fear, no greed, no herd mentality. Every decision is based on statistical probabilities, data, and mathematics. That’s why Renaissance Technologies can maintain consistent profits in all market conditions.

Looking at Jim Simons’ journey, I realize that a data-driven approach truly changes how we trade. The principles he applies—from detecting anomalies to risk management—are valuable lessons for anyone looking to improve their trading strategies. That’s why industry insiders continue to learn from Jim Simons to this day.