VOOG's stronger performance in 2026 is attributed to its index methodology, which led to a lighter weighting in Apple (6.4% vs. VUG's 12.3%) and a reallocation towards AI-driven semiconductor winners like Nvidia and Broadcom. Apple's underperformance relative to AI stocks has dragged VUG's returns. Despite VUG having a lower expense ratio (0.03% vs. VOOG's 0.07%), the difference in index construction has been the primary driver of the performance gap. Over a five-year period, VOOG is up approximately 88% compared to VUG's 80%.