Investors are looking for evidence of supply disruption in crude markets as the conflict enters its sixth day.

Critical energy infrastructure in Israel and Iran has not escaped unscathed from the first few days of the countries' escalated conflict. Worst-case scenarios have yet to be realized, but the war is already having a notable impact on energy production and exports in both countries.

That scenario now appears alarmingly close. On the evening of June 12th, Israel launched dozens of air strikes on Iranian military and nuclear sites. The attack threatens to inflame the Gulf, which pumps a third of the world’s oil. Brent crude, the global benchmark, rose by 8% on June 13th, to $74 a barrel (see chart). How high might it now go?