s&p 500 - SERP Analysis

https://www.spglobal.com/spdji/en/indices/equity/sp-500/

https://finance.yahoo.com/quote/%255EGSPC/

https://www.cnbc.com/quotes/.SPX

https://en.wikipedia.org/wiki/S%2526P_500

https://www.google.com/finance/quote/.INX:INDEXSP%3Fhl%3Den

https://www.slickcharts.com/sp500

https://fred.stlouisfed.org/series/SP500

https://www.bloomberg.com/quote/SPX:IND

https://www.investing.com/indices/us-spx-500