S&P 500 In Toppers’ List SPDR S&P 500 ETF Trust SPY, Vanguard S&P 500 ETF VOO and Vanguard Total Stock Market ETF VTI amassed about $1.52 billion and $3.87 billion in assets in September. Vanguard S&P 500 ETF (VOO): ETF Research Reports The key reasons for such underperformance were the Fed’s indication that it will continue its steep rate hike momentum to contain inflation despite the economic growth concerns.