I just read this article where alternatives to investing SPY are discussed (https://www.finstead.com/posts/SPY-ETF-review). My thought after reading this was, SPY is narrow (only 500 stocks) and relatively expensive (vs. IVV and VOO). Why do people choose to invest in SPY vs. IVV and VOO? Is it for liquidity reasons?
S&P 500 is the golden standard index for the domestic US market. SPY has been around for a long time. A lot of options expirations and SSF's are available for SPY. Good for institutions that want/need to hedge exposure or construct more complex structured positions around the ETF.