Both C. Hafner and Umicore are renowned producers of gold bars that provide high-quality products that meet the strictest standards for quality and authenticity. Basically, there are few significant differences between C. Hafner and Umicore gold bars.
Some minor differences are:
The options in weights, C. Hafner issues a 2 gram gold bar, where Umicore opts for the 2.5 gram gold bar. In addition, C. Hafner provides a Smartbox (of 25x 1 gram) and Smartpacks of 10 x 1 gram and 20 x 1 gram.
Price, the C. Hafner gold bars tend to be comparatively slightly cheaper than the Umicore gold bars.
Familiarity, although both suppliers are very well known, Umicore is just a bit better known within the Netherlands.