Watch List notes:

SWITZERLAND. Confederation, 1848-. Proof reserve note of 500 Francs 1 august 1949 by Hans Erni. Serie 4M, serial number 012352. Pick -; Richter PR2b. RRR UNC Dated and numbered in the margin. Unpriced by Richter, only three others known, one in the Swiss National Bank collection, and two in private hands. During the Second World War, the Swiss National Bank commissioned the two painters – Victor Surbeck and Hans Erni – to design new notes. While the 1000 Francs, 100 Francs and 50 Francs notes went into print, the 500 Francs note did not progress beyond the proof stage. None of the notes were ever put into circulation. (https://www.snb.ch/en/iabout/cash/history/id/cash_history_serie4#t3).