Shaken by fresh anxieties over artificial intelligence and potential cracks in credit, all while trading at historically high valuations, markets now must contend with a spiraling military action in Iran that threatens to destabilize global shipping and stanch travel. “This is all coming at a fragile time as investors are becoming more cautious,” said Dec Mullarkey, managing director at SLC Management. “US equity markets are already very sensitive to threats of technology disruption and emerging credit stress, so the prospects of higher commodity prices could force a selloff as investors rein in risk.”