Much of those losses likely stemmed from the transaction by which Pfizer got rid of its 80% stake in Zoetis during the quarter. At the end of June, Pfizer agreed to accept 405 million shares of its own stock in exchange for almost 401 million shares of Zoetis stock that Pfizer Inc. (NYSE:PFE) owned, essentially offering a small premium to encourage exchanges for Zoetis shares and thereby temporarily inflating the Zoetis stock price. With the offer over, it was reasonable for investors to take away that temporary premium and send shares somewhat lower.