Why should you pay attention to the S&P 500?

When the index falls, crypto usually plummets 2-4 times more. When the S&P rises steadily, crypto often moves 2/3 times faster than the index.

The correlation is currently around 0.5-0.8, but during panic or major events, it can reach 0.9+.

Bottom line: not watching the S&P is like trading altcoins without knowing where BTC is heading.