Gold Refineries

The Swiss refiners produce 60-70% of the gold bars in the world. There are four major Swiss refiners, Argor, Valcambi, PAMP and Metalor. Three of these are in Ticino, which is the Italian part of Switzerland. The major reason for this location was the Italian jewelry industry, which used to dominate global jewelry production for a very long time. This is no longer the case but Switzerland has continued to dominate gold refining. Gold is today a major Swiss industrial sector and accounts for 29% of Swiss exports. Combined with a number of major gold vaults and a big domestic gold trade, this is a very important industry. This is why Switzerland is unlikely to ever confiscate gold. Why would they kill the Swiss goose that lays such valuable golden eggs?
Gold refining is a precision industry. There is zero tolerance to produce a 9999 (99.99%) content gold bar of exactly 1 kilo. Once the gold has been refined and the bars cast and stamped, the final process is to weigh each bar manually and shave off exactly the right amount of a gold flake so that the bar weighs a very tiny fraction over 1 kg. To maintain their reputation, Swiss refiners will always be slightly over. Anything that is a fraction under is obviously rejected and recast.

It matters when you have to sell back because all buyers know which to give preference to.