Indian oil, Reliance, Hindustan Petroleum, Bharat Petroleum shares rallied up to 9% as crude prices plunged nearly 15% following a US-Iran ceasefire announcement, easing fears of Strait of Hormuz disruption. This drop significantly reduces input costs for downstream companies like HPCL, IOCL, and BPCL, boosting their shares. Conversely, upstream producers such as ONGC and Oil India saw declines of up to 4%.