Klaus Gerber, CFA, is a regular contributor to the Internet site WizeGuy. This past week Gerber has been incorrectly quoted as recommending that investors buy shares in Bradford, Inc. He is unaware that this message has been placed on the site as the quote was placed as a prank by an unknown source. This is the third time this has happened over the past month and each time the stock being mentioned moved in price according to the buy or sell recommendation.

Fritz Fox, CFA, maintains and updates the WizeGuy site and has learned how to determine if the quotes being attributed to Gerber are actually valid. Several days later, he observes an investment recommendation, posted on the site, to buy Gresham, Inc. The investment recommendation is purported to be from Gerber, but Fox actually knows it to be bogus. He immediately sells 1,000 Gresham short and e-mails Gerber to inform him of the bogus recommendation. Gerber immediately issues a rebuttal, and Gresham falls by 14%. Fox's action is: