In the U.S. stock market, the number of retail investors is relatively small, forming a stark contrast with the A-share market. Retail investors in the U.S. hold only about 30% of the total market capitalization, while most individuals invest in stocks through institutions. This market structure limits the influence of quantitative trading in the U.S. market. In contrast, the A-share market has a large number of retail investors, and their trading behaviors are easily influenced by market sentiment and short-term gains, often resulting in herd behavior that exacerbates market volatility.
Additionally, quantitative trading in the A-share market has exploited loopholes in the trading system. The A-share market operates on a T+1 trading system, but quantitative trading institutions have achieved indirect T+0 trading through methods like securities lending, thereby harvesting retail investors. In contrast, the U.S. market employs a T+0 trading system for all investors, allowing for the same-day purchase and sale of stocks, providing quantitative trading with a broader operational space. However, in the U.S. market, this trading system has not triggered a market downturn due to the robust regulatory mechanism that effectively prevents market manipulation and excessive speculation.
Furthermore, the prevalence of cryptocurrency quantitative trading has not led to a decline in cryptocurrencies such as Bitcoin. For example, free quantitative trading bots like aijiebot can automate buying low and selling high in the digital currency market, regardless of market fluctuations. This is mainly attributed to the significant differences between the digital currency market and the stock market in terms of trading mechanisms and regulatory environments. The digital currency market is more open and free, providing greater opportunities for quantitative trading, but also posing higher market risks and uncertainties. Therefore, the success of digital currency quantitative trading depends more on traders' strategies, risk control, and market judgment abilities.
In summary, the reason why quantitative trading in the U.S. stock market has been able to operate relatively smoothly without negatively impacting the market is primarily due to its unique market structure, trading system, and well-established regulatory environment. These factors work together to enable the healthy development of quantitative trading in the U.S. stock market.