Swiss 20f 1930-B Gold Coin; NGC MS-67

The only true way to get this gem accurately valued is to put it up for open public auction.
Naturally if it was mine, I would not be interested in selling it.

The next best thing to do value wise, is to have a look at major auction houses' records for near equivalent coins that have been sold.
Market trends since each near equivalent sale have to be taken into account, as well as inflation trends. From all of this information, a rather tenuous graph of price Vs. condition can be drawn, and interpolations made, to arrive at a guesstimate of the value of the coin in question.

This process can involve quite some work, which can only be justified for very expensive coins. It is usually only done before a particularly valuable coin is sent to auction, to get some idea of a fair estimate.

This coin is very near to the bullion value (maybe +10%), even in MS67.

It is a very common date with a mintage of 3,371,764 pcs.

I would not put it at a public auction as the seller comission would eat up the premium for the grade, which is very thin.

I agree, these are super common, and even in BU, can be bought for melt. I bought one recently in MS-65 for spot plus 10%. I would think an MS-67 could bring spot plus 25%.