IVV is the iShares ETF tracking the S&P 500 and is among the largest ETFs by assets, together with VOO and SPY. It holds the same 500 large US companies as other S&P 500 funds and has an expense ratio equal to VOO and well below SPY. IVV is an open-end fund, so it can reinvest dividends immediately, whereas SPY is a unit investment trust that holds dividends in cash until the next distribution. For most investors the difference in long-term returns between IVV, VOO and SPLG is expected to be very small. The choice between them usually depends on the brokerage platform, trading costs and personal preference.
