Yes, several recurring patterns can indeed be identified in these major stock market crashes:

1. Prior excessive speculation – Almost all major crashes were preceded by periods of excessive optimism and speculation. The Roaring Twenties before 1929, the technology bubble of the late 1990s, the real estate speculation before 2008.
2. Leverage and debt – Excessive borrowing often plays a crucial role. In the 1920s, investors bought stocks on credit; before 2008, it was highly complex leveraged financial products.
3. New technologies or markets – Many crashes follow phases where new technologies or markets were overvalued (Dotcom bubble, fintech innovations before 2008).
4. Regulatory gaps – Crises often develop in areas with insufficient oversight or regulatory blind spots.
5. Psychological factors – Panic and herd behavior significantly amplify the downward trend once it has begun.
6. Global contagion – With increasing globalization, crises spread internationally more quickly. What began in Thailand in 1997 soon affected all of Asia; the US mortgage crisis in 2008 became a global financial crisis.
7. Liquidity crises – In almost all cases, a point is reached where liquidity suddenly dries up and assets can no longer be sold at reasonable prices.
8. Time intervals – Interestingly, major crashes seem to occur approximately every 8-10 years, partly related to the economic cycle, but also because institutional memory fades and new generations of investors enter the market without experience of previous crashes.
9. External shocks – Some crashes are triggered or intensified by unpredictable external events, such as the 2020 pandemic.

These patterns suggest that markets are inherently cyclical and that despite various triggering factors, similar underlying dynamics are at work.