The Supreme Court rules that the Government Service Insurance System (GSIS) exceeded its rule-making authority when it issued provisions affecting survivorship benefits for certain family members of deceased members. The decision invalidates Section 24.2.2 of the Revised Implementing Rules and Regulations (IRR) of Republic Act No. 8291, the GSIS Act. Under the challenged GSIS rule, secondary beneficiaries are excluded from survivorship benefits when the deceased member had at least three but less than 15 years of service. In a ruling written by Associate Justice Henri Jean Paul Inting, the Supreme Court Third Division declares the challenged IRR provision ultra vires, meaning it goes beyond what GSIS is allowed to regulate under its enabling law. The Court’s decision therefore overturns the GSIS interpretation that denies secondary beneficiaries benefits in the specified service-length range. The ruling focuses on the legality of the GSIS implementing rule, rather than on unrelated aspects of eligibility or benefit computation. The Supreme Court’s decision stands as a binding interpretation of the GSIS Act’s coverage for secondary beneficiaries in these circumstances.