For nearly a year since the Hamas attack on Israel on Oct. 7 and the start of the fighting in the Gaza Strip, investment strategists have warned that a wider war could break out in the Middle East, crimping the world’s oil supply and sending shock waves throughout the global economy.

The markets have generally shrugged off the potential of a broader conflict: The price of oil has remained largely subdued over the past year, with traders reassured by the world’s plentiful supply.

But after Iran launched a barrage of missiles at Israel on Tuesday, oil prices began to rise as the market appeared to factor in the risk of a growing regional conflict. After President Joe Biden said on Thursday that there had been “discussions” about support for an Israeli attack on Iran’s oil facilities, the price of Brent crude, the global oil benchmark registered its biggest weekly gain in more than a year.

“Investors are finally paying attention to the Middle East after having decided it wasn’t going to move the needle,” said Tina Fordham, a former chief global political analyst at Citi who now runs an independent consultancy.

“It’s not a perfect storm yet,” she said, “but it’s a constellation of risks coming together at a time when market systems still haven’t gotten comfortable that we’ve avoided a hard economic landing.”

Everyone is watching Israel’s next move. Attacking Iran’s oil infrastructure or nuclear facilities, for example, would intensify the conflict. Biden has said he will not support an attack on Iran’s nuclear sites, and Friday cautioned Israel against hitting Iran’s oil fields. “The risk is not zero, which means it’s high enough to consider different scenarios that range from all-out conflict that curtails energy access to a peaceful off-ramp,” said Ronald Temple, chief market strategist for Lazard’s financial advisory and asset management business.

Oil prices are the biggest global economic risk factor. Iran produces about 2% of the world’s oil supply, which it sells mostly to China. But the greatest liability to the global economy would be if Iran blocked access to the Strait of Hormuz, which connects the Persian Gulf to the Arabian Sea, because about 20% of the world’s oil passes through there.

Oil prices are still lower than a year ago, mostly because the United States and other countries have ramped up production and demand in China, the world’s biggest oil importer, has continued to fall as its economy has slowed. Saudi Arabia and seven other oil producers have also agreed to unwind some of their production cuts, although the plan has been delayed.

“Even though there’s a lot of oil in the world right now, a massive regional war could take more oil offline than there is spare capacity,” said Matt Gertken, chief strategist at BCA Research.

That could fuel inflation. Oil prices are a major component of food prices, for example. At a moment when much of the world is starting to get inflation under control, a sustained increase in oil prices could set off a new bout and potentially affect interest rates.

Analysts at Capital Economics suggested that oil prices would most likely need to reach $90 a barrel to become a factor for central banks. As of Friday, the price of Brent crude was $78 per barrel.

Stephen Schork, a trader who advises heavy industrial users of oil, such as fertilizer or natural gas companies, on how to hedge risks, says it’s “imperative to act now” to protect against a jump in prices. He is recommending that they use a specific options strategy known as a “zero cost collar.”

Companies are watching for how the conflict affects the U.S. election, the outcome of which could have huge consequences for trade relations, taxes and regulation. Neither a spike in oil prices nor a heightened sense of global turmoil would help Vice President Kamala Harris’ campaign.

Markets have tended to shrug off geopolitical risk. Despite the war in Ukraine and the fighting in Gaza, stocks have been at historic highs. Oil prices spiked after Israel and Iran exchanged blows in April, but quickly fell.

Quincy Krosby, chief global strategist for LPL Financial, says the philosophy on trading room floors, which is echoed by companies, tends to be “It doesn’t matter until it matters.”

But, she says, at some point it does matter: “The question is how far does it go?”