The U.S. administration has told regional mediators it will not return to the memorandum of understanding signed with Tehran last June, effectively ending prospects for reviving the agreement, which collapsed weeks after being signed at the Palace of Versailles. Crude oil rose above $88 a barrel and global equity indices fell as markets assessed the risk of supply disruptions through the Strait of Hormuz. The memorandum, helped negotiated by Vice President J.D. Vance, was designed to reopen the strategic waterway and begin talks on Iran's nuclear program in exchange for sanctions relief and access to Tehran's frozen assets. It unraveled after Iran targeted shipping traffic to assert control over the strait, leading U.S. President Donald Trump to pursue "maximum economic pressure." Iran's Islamic Revolutionary Guard Corps has tied any reopening of the waterway to Washington's return to the memorandum and an end to what it calls obstruction. Mediation efforts by Pakistan, Oman and Qatar produced no announced breakthrough, while competing Iranian and Omani accounts differed over whether Tehran and Muscat reached a transit agreement. The diplomatic impasse coincided with the U.S. Treasury Department's August 25 launch of "Operation Economic Pariah," targeting approximately 60 entities and extending secondary sanctions (penalties on third parties) across five sectors. Shipping traffic rose to 10 visible cargo vessels on Wednesday from eight on Tuesday, but remained below the 10-day average of about 15. A tanker was struck by an unidentified projectile on Thursday, and the fire was later extinguished. August 28 marks six months since strikes targeting Iran, a symbolic date that analysts believe could lead both sides to reassess a conflict with no clear resolution horizon.