〔Overnight Brief〕Second Tanker Struck in Hormuz as Iran Brands Transponder-Off Vessels Hostile; WTI +1% to $91.88, Brent $103.7, BP Pulls From Riyadh Congress — Partial US-Iran Deal Tested by 24-Hour Strike Stack

0. Overnight Arc

The board's overnight shock stack built in three layers: a second tanker struck by a projectile in the Strait of Hormuz inside 24 hours, with the Sohar-anchorage drone hit reclassified as an attack and crew evacuation underway ^[1][2][3][4]; Saudi Arabia's Dammam King Fahd International Airport hit, plus a separate projectile on Riyadh's King Khalid International Airport Terminal 4 that triggered a fire, with a cruise missile intercepted by air defenses deployed around the airport ^[5][6][4]. WTI rose 1.00% to $91.88/bbl, Brent climbed to $103.7, with year-to-date benchmark gains above 70% ^[7]; BP and other oil chiefs withdrew from the World Petroleum Council congress in Riyadh after 12 were killed in an earlier Houthi strike ^[8][9]. Negotiation track opened a sliver: Iran says the US accepted "some" Hormuz conditions; the IRGC simultaneously ruled transponders-off equals hostile ^[10][11].

1. Strait of Hormuz: Incidents and Rules

• **[ESCALATED] Tanker strike count.** UKMTO received a report of a tanker hit by an unidentified flying object in the strait, all crew reported safe on the port-side strike ^[2][3]. WANA reported a second supertanker struck a sea mine in Hormuz ^[12]; Rudaw and the Around Prague wire framed the 24-hour count as "second tanker hit" ^[13][14]. Source-quality flag: the drone/mine/projectile distinction is unsettled across wires ^{[1][12][2][3]}.
• **[NEW] IRGC navigation rule.** Iran's IRGC Navy declared any vessel switching off navigation and identification systems in the Strait of Hormuz will be treated as a hostile target ^[10]. Mechanism: forces AIS-disabling tankers into the open or into Iranian response corridors.
• **[NEW] Crew pricing signal.** A seafarers' union official told NPR crews are being offered "big money" to transit Hormuz ^[15] — risk premium surfacing in labor markets, not just freight rates.
• **[ONGOING] Sohar reclassification.** UKMTO upgraded the Sohar-anchorage drone strike on a tanker to an "attack" incident; local authorities are assisting crew evacuation ^[4].
• **[NEW] Strategic framing.** The US touted Iran's "absolute isolation" alongside the fresh Hormuz tanker blast ^[13]; CNN framed Tehran as "trying to regain its stranglehold on shipping" after Gulf oil increasingly moved out ^[16]; the New York Post reported Iran set a supertanker ablaze after a US action against a ship "breaking blockade" ^[17].

2. Saudi Strikes and the Energy Stage

• **[ESCALATED] Dammam King Fahd International Airport** was hit, per the Saudi civil aviation authority ^[5]. Riyadh's King Khalid International Airport Terminal 4 was struck by an unidentified projectile that caused a fire; a cruise missile was intercepted by air defenses, per coalition spokesperson Turki al-Maliki ^[6][4]. A second explosion was heard in Riyadh the same afternoon ^[18].
• **[ESCALATED] Riyadh pullouts.** BP and other oil chiefs withdrew from the World Petroleum Council congress in Riyadh after 12 were killed in an earlier Houthi strike on the Saudi capital's main airport ^[8][9]. Bloomberg's Alex Koccharov and Abeer Abu Omar framed the episode as raising risks to Gulf shipping, energy infrastructure, and Saudi investment ambitions ^[19].
• **[NEW] Counter-strike reported.** Houthi-affiliated media said Sanaa airport was struck, per Reuters via the overnight tracker ^[4].
• **[ONGOING] Air-defense strain.** Saudi Arabia acknowledged interceptor-missile stocks are "insufficient" ^[4], flagging sustainability of the defense cadence.
• **[NEW] Regional energy diplomacy.** Saudi Energy Minister signed three energy-cooperation MOUs with Kuwait, Qatar, and Egypt, per Saudi state news agency ^[20] — a parallel track to the kinetic events.
• **[ONGOING] Yemen frontier.** Houthi armed forces said Saudi Arabia conducted three airstrikes on two districts in Yemen's Taiz province ^[21].

3. Negotiation Track and the "Absolute Isolation" Frame

• **[NEW] Iran read.** Supreme National Security Council secretary Ali Akbar Rezaei said the US has accepted "some" Iranian conditions to reopen the Strait of Hormuz but that responses on the rest are "insufficient" ^[11][4]. Iran's foreign minister offered to help drive Saudi-Houthi political dialogue ^[4].
• **[NEW] Iran pre-positioning.** Per the overnight tracker, Iran's top security official warned that any new war would see strikes on regional cables and data centers; separately accused the Trump administration of "smuggling" oil through Hormuz ^[4].
• **[NEW] US framing.** US messaging touted Iran's "absolute isolation" alongside the fresh Hormuz tanker blast ^[13].
• **[ONGOING] Back-channel.** Iran's president discussed the regional situation in a call with Oman's Sultan ^[22]; Israeli media reported Netanyahu-Trump calls "multiple times this week" ^[4].
• **[ESCALATED] Former US envoy warning.** Former White House Middle East Coordinator Brett McGurk told Bloomberg This Weekend that the Riyadh airport attack "underscores the growing threat from Iran-backed Houthi militants," and that hardline Tehran leadership complicates a negotiated end ^[23].
• **[NEW] Bloc posture.** A four-country bloc condemned continued Houthi attacks on Saudi Arabia ^[4] — country list is single-source via Chinese-language relay and the translation is unverified.

4. Market Read and What Would Falsify

• **[NEW] Spot reaction.** WTI rose 1.00% to $91.88/bbl; Brent climbed to $103.7; YTD benchmark gains exceed 70% on the persistence of the US-Iran conflict and the absence of a resolution path ^[7]. Same wire noted Middle East producers have restored Hormuz crude exports near pre-conflict levels, but the rising tanker-strike count threatens those flows ^[7].
• **[NEW] SPR tool.** The US Department of Energy said it will approve emergency exchanges of up to 4 million barrels from the Strategic Petroleum Reserve to offset supply disruptions from Hurricane Isaias, which cut power in three US states and killed at least four ^[7].
• **[ONGOING] Freight/capacity squeeze.** A research note flagged that rising Middle East crude outbound volumes plus lengthening ship-to-ship transfer queues are crowding out tanker capacity, sustaining elevated freight rates ^[24].
• **Falsification test.** (i) a third tanker incident inside 48 hours that the IRGC publicly attributes to a transponder-off vessel, validating the rule and lifting premia; (ii) the US-Iran partial-condition track producing a written transit ceasefire that pulls the 70% YTD bid out of oil ^[10][11][7]; (iii) Saudi interceptor-missile depletion forcing an explicit resupply request or visible US/Israeli intercept support ^[4].
• **Source-quality flags.** The Iran-side read of US acceptance is single-channel via Rezaei; the IRGC transponder framing is via Iranian state-aligned wires; the Reuters-sourced Sanaa airport strike is a Houthi-affiliated-media claim; the four-country bloc list is unverified translation ^[10][11][4]. Treat the negotiation track as a band, not a point.