Overnight vs Intraday Return Explorer | SpyTomorrow
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Night vs Day: the Overnight Return Explorer

What happens if you only own the market while it sleeps? Compare buy the close, sell the open against buy the open, sell the close for any ticker, using the same Yahoo Finance daily data yfinance pulls.

Overnight close → next open Intraday open → close Buy & hold close → close

Methodology. Overnight compounds every close→next-open move; intraday compounds every open→close move. Raw (unadjusted) prices are used, matching the published overnight-anomaly studies. Dividends land in the overnight session on ex-div dates and are not reinvested here, so the overnight curve is slightly understated.

Reality check. The naive version of this trade means ~250 round trips a year — spreads and slippage matter, and the pattern is regime-dependent. This is an educational visualization, not investment advice.