Ferdinand Alexander "Sandro" Araneta Marcos III (UK: /ˈmɑːrkɒs/ MAR-koss, US: /-koʊs, -kɔːs/ -kohss, -kawss, Tagalog: [ˈmaɾkɔs]; born March 7, 1994) is a Filipino politician who is the representative of Ilocos Norte's 1st congressional district since 2022, and the eldest of three sons of Philippine President Ferdinand R. Marcos Jr. and First Lady Liza Araneta Marcos.