虎嗅

Quantitative analysis reveals why many investors fail collectively; where should individual retail investors go from here?

原文:量化为何集体翻车,散户何去何从?

Summary of Key Points

Quantitative trading can achieve annual returns of 16% thanks to algorithms, but it can also result in losses of 20% in a single month due to “strategic congestion” (too many people using the same method). It doesn’t target individual retail investors specifically; instead, it targets any “predictable trading behavior.” What ordinary people should learn is not to copy its strategies, but rather the strict rules of risk control.

Breakdown and Explanation

1. How does quantitative trading earn 16%?

Quantitative trading essentially involves using computer algorithms to replace human stock trading: Programmers write investment logic into code (for example, “buy when the stock price falls below the 20-day moving average, sell when it rises above the 30-day moving average” or “certain stocks are more likely to rise on Mondays”), and then use big data to test this logic against market data from past decades to see if it’s effective. For instance, an algorithm might detect that small-cap stocks tend to experience short-term increases between 9:30-10:00 AM, so it automatically buys at 9:30 AM and sells when the price rises slightly around 10:00 AM, earning a 0.1% per day. Over 200 trading days in a year, this can add up to a 16% return. Moreover, robots don’t act emotionally like humans—they won’t sell too early out of panic or hold on too long due to greed, making their execution fast and stable.

2. Why can strategic congestion lead to losses of 20%?

“Strategic congestion” is similar to thousands of people trying to cross a narrow bridge at the same time: If only 10 quantitative funds use a particular strategy, the impact on stock prices will be minimal. However, if 1,000 funds all adopt the same strategy (such as investing in low-volatility, high-dividend stocks), the prices of those stocks can soar. Once market conditions change (for example, interest rates rise and these stocks become less attractive), all the funds will trigger sell signals simultaneously. With no buyers, stock prices plummet. In 2023, a popular quantitative strategy resulted in an average loss of 20% for similar funds within a month because too many investors were using it, leading to a market collapse.

3. Does quantitative trading not target retail investors?

The statement that it “doesn’t target retail investors” doesn’t mean they’re unaffected; rather, its focus is on any predictable trading behavior, not the retail investor group as such. For example, retail investors often buy when stocks are rising and sell when they’re falling. Quantitative algorithms can identify this pattern and buy before the price increases, then sell once retail investors join in, profiting from their actions. However, if retail investors’ behavior is random, quantitative trading has less impact. Conversely, if institutional investors’ behavior follows a predictable pattern (such as regular asset allocation), quantitative trading can also target them.

4. The most important lesson to learn: Risk control first

Quantitative funds succeed not by earning the most, but by being able to withstand losses. There are two key risk control principles that ordinary people should adopt:

  • Set stop-loss limits like a lifeline: For example, a quantitative fund might be programmed to stop trading immediately if a single strategy results in a 5% loss, avoiding further losses.
  • Diversify your investments: Instead of relying on one strategy, use multiple strategies (e.g., some targeting large-cap stocks and others small-cap stocks). This way, if one strategy fails, others can compensate for it. Similarly, investors should diversify their portfolio and not put all their money in one stock or industry.

Final Conclusion

Quantitative trading is like “smart robots,” but they can also make mistakes. Ordinary people shouldn’t envy its high returns; learning to control risks from quantitative trading strategies is far more valuable than simply copying them.