The spot price represents the 'industrial wholesale' rate for the metal itself. However, mints charge additional fees to transform these raw metals into the finished products desired by investors.
The most straightforward and cost-effective products to produce are large bars, such as 100 oz. silver bars or 1 kilo gold bars. These larger bars typically have the smallest premiums above the spot price. In contrast, smaller products generally carry higher premiums due to the increased complexity and labor involved in their production.