Data: gold/fastmarkets_fob_prices.parquet, gold/marketview_daily.parquet
Source: Fastmarkets Physical API
Basis roll: each futures contract is never used during its expiry month. Corn/wheat: Dec–Feb → /H, Mar–Apr → /K, May–Jun → /N, Jul–Aug → /U, Sep–Nov → /Z. Soybeans: Nov–Dec → /F, Jan–Feb → /H, Mar–Apr → /K, May–Jun → /N, Jul → /Q, Aug → /U, Sep–Oct → /X.