Iran has blacklisted 45 oil tankers for alleged transit violations in the Strait of Hormuz, placing major Gulf energy shippers under threat of fines, detention and cargo confiscation. The action was announced by the newly formed Persian Gulf Strait Authority (PGSA), which Tehran established to manage traffic through the strait and enforce its transit rules. Vessels conducting ship-to-ship transfers with blacklisted tankers may also be added to the list. Named operators include Saudi Arabia’s Bahri, ADNOC Logistics and Services and its Navig8 Tankers subsidiary, Norway’s Klaveness Ship Management, Stolt Tankers and South Korea’s Sinokor. The affected fleet includes Very Large Crude Carriers, LNG and LPG carriers, and clean product tankers. The PGSA did not identify the specific violations by vessel, citing earlier Iranian compliance demands without providing a detailed breakdown. The move comes against the backdrop of a regional conflict now six months old, intensified U.S. naval enforcement around the strait and Washington’s threat of potentially the toughest sanctions in history against Iranian oil exports. The authority’s formal blacklist and enforcement mandate could represent a structural escalation of Iran’s longstanding informal pressure on Hormuz traffic.