Capital gains taxation: source State taxes immovable and PE linked gains, otherwise residence State retains exclusive taxing right. Article 13 allocates taxing rights for capital gains: source State taxation applies to gains from immovable property situated there, gains attributable to movable property of a permanent establishment (and dispositions of that establishment), and specified transfers of ships or aircraft and certain share interests where asset value or negotiated ownership thresholds are met; otherwise the residence State has exclusive taxing rights for gains not covered by these specific provisions.