If you are choosing between Vanguard 500 Index Fund ETF (NYSEARCA:VOO) and iShares Core S&P 500 ETF (NYSEARCA:IVV), the index is the same. Both track the S&P 500. Both charge 0.03% in expenses. Yet over the past year, IVV returned 32.22% while VOO returned 32.12%. Over ten years, the gap flipped the other way: VOO ... IVV Beat VOO by 10 Basis Points Last Year and Securities Lending Is the Reason Most Investors Miss