Don’t panic.

That’s the first rule investors should follow when considering how to invest when chaos strikes, and the Iran war is no different, market pros told Business Insider.

The conflict-fueled sell-off picked up again on Thursday as the war sent oil prices back to $100 a barrel. The S&P 500 is now down nearly 3% for the year. As of February, the index was on track for one of its worst year-to-date performances in decades.

Investors have been quick to sell the broader index and purchase volatility-linked ETFs, according to a report from VandaTrack Research, which tracks retail investor flows. But the most important thing for investors to do is not panic and make dramatic changes to their portfolios,…