Trading hours: each regular open → that day’s close, normally 9:30am–4pm New York time. After hours: the previous close → the next regular open, including weekends and holidays. Each line compounds only its own session returns, starting from the same $100 at the first visible daily close. Horizontal zooming and panning rebase all lines to that common starting point; the returns below follow the visible date range.

Data: Yahoo Finance SPY daily prices, from 29 January 1993. SPY is the tradable S&P 500 proxy. The two session factors multiply to the buy-and-hold factor; their percentage returns do not add. Daily refresh uses completed prior-day bars. Returns exclude trading costs, taxes and interest on cash.

Chart data (JSON) · Prices & returns (CSV)