S&P 500 daily close (FRED SP500), WTI crude oil (FRED DCOILWTICO), and USD/EUR spot rate (FRED DEXUSEU), https://fred.stlouisfed.org/series/SP500, https://fred.stlouisfed.org/series/DCOILWTICO, https://fred.stlouisfed.org/series/DEXUSEU, 4 January 2021 – 18 September 2026, downloaded 27 Sep 2026.