U.S. forces conducted another wave of strikes on Iranian targets on Sunday, with Tehran then targeting U.S. facilities in Bahrain, Kuwait, Oman and Jordan on Monday.
Brent crude jumped early on Monday to nearly $80 per barrel before paring some of those gains to trade around $78/bbl - a response that, like last week's, seems fairly restrained, with prices still below levels seen before the shaky interim peace deal was signed in mid-June.
But chaos and uncertainty are hanging over Hormuz once again amid conflicting claims around the status of shipping. While Iran said it had closed the strait, U.S. President Donald Trump said it remained open.
Tanker traffic data so far appears to align with Tehran's view. Transits fell dramatically last week as the initial U.S.-Iran tit-for-tat attacks unfolded, and they have remained low over the weekend. Only six vessels transited the waterway on Sunday, the lowest number in five weeks, according to ship-tracking data from Kpler.
Elsewhere, volatility in semiconductor stocks looked set to continue as South Korea's chip-heavy KOSPI index closed down nearly 9% on Monday, dipping under 7,000 for the first time since early May. It also re-entered bear market territory, finding itself some 25% below its June 22 peak.
The KOSPI's slide was partly driven by a more than 15% plunge in memory chipmaker SK Hynix, its biggest one-day decline on record, which follows a more than 12% jump in its U.S.-listed shares after their Nasdaq debut last Friday.
Global equities at large looked cautious and bond yields rose on Monday morning. Wall Street futures were in the red before the bell and European shares opened lower.
Investor focus will now shift to the second-quarter earnings season, which gets underway in earnest this week, notably with a bank earnings bonanza on Tuesday.
Tuesday will also bring U.S. consumer price inflation data for June, with the core measure, which strips out energy prices, likely to be watched closely for a read on underlying price pressures. The release follows a recent hawkish turn at the Federal Reserve, where new chair Kevin Warsh last month reaffirmed a commitment to price stability.