VOO and IVV Show Identical S&P 500 Returns
Two major ETFs track the same index with a 0.03% fee and nearly equal performance, but their internal structures differ significantly.
Vanguard S&P 500 ETF and iShares Core S&P 500 ETF returned 17.25% and 17.24% respectively over the last year. Both funds charge an expense ratio of 0.03%. They track the identical S&P 500 index. The performance gap is negligible for most investors. The structural differences, however, are not.
Institutions often favor the iShares fund for large block trades. Tighter bid-ask spreads can outweigh annual fee savings on nine-figure allocations. The Vanguard fund pools securities lending benefits across its share classes. The iShares fund directs all lending revenue to ETF holders.
Corporate structures differ significantly
Vanguard’s ETF is a share class of a larger mutual fund. That mutual fund held $1,675,038 million in net assets as of June 30, 2026. The iShares fund is a standalone trust. It held approximately $888 billion in net assets at the same date. This distinction affects how each fund manages tax lots.
The Vanguard structure allows the mutual fund side to absorb inflows and outflows. The ETF uses in-kind creation and redemption to exit low-basis lots. The iShares fund handles tax lots entirely through its own creation and redemption baskets. It processes these trades through DTC participants like National Financial Services and Charles Schwab.
Brokerage choices influence selection
Your broker determines which fund is more convenient. Fidelity and Schwab customers often find the iShares fund easier to trade. Vanguard users benefit from commission-free trades on the Vanguard fund. They can also perform tax-free share-class swaps between the ETF and mutual fund.
The GN auto markets/indices: stock index data confirms both funds track the same underlying assets. The choice depends on your brokerage and trading style. For most retail investors, the outcome is the same. For large institutions, the plumbing matters.
