Overview
- The Vanguard S&P 500 ETF (VOO) passed $1 trillion in net assets on June 3, marking a new scale milestone for a single ETF.
- VOO overtook State Street’s SPDR S&P 500 ETF Trust (SPY) in assets in February 2025 and has kept net inflows that left SPY as a close but smaller rival.
- A small expense-ratio gap—VOO’s roughly 0.03% versus SPY’s roughly 0.09%—has been a major driver of long-term investor migration between the two near-identical S&P 500 trackers.
- Despite similar holdings and almost identical multi-year returns, structural differences in product wrappers affect operational details such as dividend handling and securities lending.
- The growth of giant, low-cost S&P 500 ETFs channels new passive money into the largest index names, which can raise concentration risk for everyday investors and prompt interest in alternative index or weighting strategies.