Wall Street Fear Index Surges After Israel Strikes Iran

The most widely-followed gauge of Wall Street fear and uncertainty spiked on Friday, as Israel's surprise strike on Iran sent geopolitical tensions back to the top of investors' worry list.

The Cboe Volatility Index, which tracks S&P 500 options contracts and trades under the ticker VIX, jumped by 3 points to 21 in early trading. That's a surefire sign the market is feeling on edge: Any reading of above 20 tends to indicate relatively high volatility.

The VIX was rallying after Israel hit Iran's nuclear program and military leadership overnight. The attacks have triggered a surge in oil prices and sent stocks tumbling, although some analysts believe the selloff could be short-lived.