HD Hyundai (KRX:267250) amended a March 26 disclosure to report that subsidiary HD Hyundai Oilbank's funding-support guarantee to its petrochemical joint venture — recently renamed from HD Hyundai Chemical to H&L Advanced Co. — falls from ₩300bn to ₩250bn, cutting the guarantee from 5.1% to 4.2% of Oilbank's own equity. The stated reason is that Oilbank's ownership stake in the venture dropped from 60% to 50% as of September 2; the guarantee amount is contractually tied to that ownership share. Oilbank's total outstanding guarantees across its affiliates now stand at ₩2,455.6bn, still dominated by a ₩1,500bn facility backing HD Hyundai E&F's natural-gas purchase contract with KOGAS through 2034. The filing traces back to a Korean government "corporate vitality" special-law restructuring plan HD Hyundai Chemical and Lotte Chemical launched together to consolidate their overlapping petrochemical capacity.