From Google:

1. Immediate Impact on Investors and Wealth
Widespread Retail Losses: Millions of investors, particularly millennials and Gen Z, who have high exposure to crypto, would see significant wealth evaporated.
Loss of Confidence: A crash could cause younger generations to lose faith in financial markets, potentially leading them to withdraw from investing entirely.
Retirement Security Risk: Retirement accounts that have invested in crypto-backed products would face severe losses.
2. Contagion to Traditional Finance
Corporate Treasury Losses: Companies that have added Bitcoin to their balance sheets, such as MicroStrategy, would face extreme margin pressure and potential insolvency.
Systemic Risk to Institutions: While large banks have mostly stayed on the sidelines, massive asset managers, pension funds, and ETFs now hold Bitcoin. A crash could cause liquidity issues for these entities.
"Death Spiral" Effect: A rapid decline could trigger a cascade of forced selling, liquidating leveraged positions, and forcing miners to shut down.
Stock Market Correlation: Because Bitcoin currently trades highly correlated with tech stocks, a crash would likely drag down broader equity markets.
3. Economic and Regulatory Consequences
Severe Regulatory Crackdown: Massive investor losses would trigger immense pressure on lawmakers to impose strict regulations on crypto exchanges, brokerages, and issuers like BlackRock.
Unwinding of "Crypto-Collateralized" Lending: With billions in crypto-collateralized loans, a crash would cause a massive, rapid deleveraging, forcing borrowers to dump other assets to cover losses.
Crypto Winter: The broader crypto market (altcoins) would likely follow Bitcoin down, resulting in a prolonged period of extremely low prices and reduced liquidity.
4. Limited Impact on Overall Financial Stability
Banking Sector Exposure: Although crypto is embedded in the system, most traditional banks have limited direct exposure, reducing the likelihood of a 2008-style systemic banking collapse.
Tech Sector Contagion: The most severe damage would likely be confined to tech-heavy, high-growth portfolios rather than systemic banking, though this would still impact the real economy through lower consumer spending.