A new stock named A.F.P. appeared on the bulletin board of the Detroit stock exchange. Little was known about it except that the initials were rumored to stand for American Fire Protection. Despite the relative mystery, the new listing prompted lively trading. It opened at six, rose rapidly to 12, dropped down to 2, and finally climbed back upward to 8, where it remained. But eventually someone thought to contact the Michigan Securities Commission to ask if this new stock had been sanctioned by them. They responded that A.F.P. was not authorized, so sales of it were illegal and each broker was responsible for his own losses. At which point, word got around that the initials actually stood for April Fool Preferred or All Fools Preferred. The identity of the prankster who listed it on the board was never discovered.