The idea of switching smaller items (single—or stacks of—cards, envelopes, billets, corners of cards or bills, etc.) under cover of a larger prop (e.g., tray, jumbo card, book, matchbox) while passing that prop from one hand to the other was used in a number of tricks and routines by J. N. Hofzinser. For two examples, see “The Library of German Poetry” in Ottokar Fischer's J. N. Hofzinser Zauberkünste, 1942, p. 61; translated into English by Richard Hatch as The Magic of J. N. Hofzinser, 1985, p. 68; and “The Wonderful Deck” in J. N. Hofzinser: Non Plus Ultra, Vol. 2, 2004, p. 199; translated into English by Dave Shepherd as Non Plus Ultra, Vol. 2, 2013, p. 227. It is unknown if Hofzinser originated this switching concept, but no earlier published instances of it have been found to date.
This switching has been reinvented many times. See, for example, Theodore Annemann's “A New Apparatus for the Pellet Switch” in his Book Without a Name, 1931, p. 38.
Don Alan created a related switch, called the “Big Deal” Switch, which incorporates the turning over of the prop, in this case a jumbo card. This switch was the method for his trick, “Big Deal”, marketed c. May 1963.