Why does a fractional basis point price variance exist between physical bullion stored in Zurich versus Miami?

Physical commodities incur real-world logistical, transport, and insurance costs. Moving gold into specific geographic vaults and fabricating it into smaller consumer retail forms, such as one-ounce coins versus large twelve-and-a-half kilogram bars, carries distinct fabrication premiums and shipping expenses. These microscopic basis point differences reflect actual physical custody logistics rather than paper market arbitrage.