Quantitative investing is the practice of using mathematical models, statistical analysis, and computational algorithms to make investment decisions. Rather than relying on qualitative judgments about a company's management team or brand strength, quantitative investors build systematic frameworks that convert raw data into actionable signals. The approach traces its roots to academics like Harry Markowitz, who formalized Modern Portfolio Theory in the 1950s, and gained mainstream traction through firms like Renaissance Technologies and DE Shaw in the 1980s and 1990s.
At its core, quantitative investing seeks to remove emotional bias from the decision-making process. Human investors are prone to well-documented cognitive errors: anchoring to purchase prices, chasing recent winners, and panic-selling during drawdowns. A quantitative system, by contrast, follows predefined rules regardless of market sentiment. This discipline is one of the primary advantages of the approach, though it requires the investor to trust the model through periods of underperformance.
The quantitative process typically begins with hypothesis formation. An investor might hypothesize that stocks with low price-to-earnings ratios outperform over time. This hypothesis is then translated into a testable model using historical data. The model is backtested across multiple time periods and market environments to evaluate its robustness. If the results are statistically significant and survive out-of-sample testing, the strategy may be deployed with real capital.
Modern quantitative investing spans a wide spectrum of complexity. On the simpler end, an individual investor might screen for stocks meeting certain factor criteria and rebalance quarterly. On the complex end, hedge funds deploy machine learning models that process satellite imagery, credit card transaction data, and natural language processing of earnings calls to generate alpha. Regardless of complexity, the foundational principle remains the same: let data and evidence guide decisions rather than intuition alone.
One important distinction is between quantitative investing and algorithmic trading. Quantitative investing focuses on what to buy and sell, using data to identify attractive securities. Algorithmic trading focuses on how to execute those trades efficiently, minimizing market impact and transaction costs. While the two often overlap in practice, they address fundamentally different problems in the investment process.