Roosevelt signed Executive Order 6102 (read the full order here) in 1933, which prohibited the accumulation of gold coins, ingots and certificates in the United States. The reason was to remove the restriction on the Federal Reserve that prevented it from increasing the money supply during the depression. In a way, this was like the modern QE programs we use today. Despite the fact that gold was not confiscated in 1933, the people who traded it actually lost when it rose higher in value shortly thereafter.
The Swiss company would have lost 40% of the value of its gold if it had tried to buy the same amount of gold with the paper money it received in exchange for the confiscated gold. The Uebersee Finanz-Korporation entrusted the gold to an American company for safekeeping, and the Swiss were surprised to learn that their gold had been confiscated. A new Treasury regulation was issued that established civil penalties such as the confiscation of all gold and the imposition of fines equivalent to twice the value of the gold seized. American gold coin dealers who try to frighten their customers into buying more expensive old gold coins prior to 1933 usually speak of “confiscation” when referring to Executive Order 6102 of April 3, 1933.