Zoetis’s stock (ZTS) climbed nearly 9% after The Wall Street Journal reported that Ackman and his Pershing Square Capital Management have taken about a 10% stake in the company and could push for a sale to a larger drug maker such as Valeant Pharmaceuticals. WSJ, which cites anonymous sources, adds that hedge fund Sachem Head Capital Management, which is run by former Ackman acolyte Scott Ferguson, is also in on the stake.

Zoetis shares continued to gain in value in after-hours trading.

Of course, Ackman has been trying for most of this year to team with Valeant (VRX) on a proposed takeover of Botox maker Allergan (AGN), in which the hedge fund manager also holds a 10% stake. Allergan has repeatedly fought off advances by Ackman and Valeant, which have offered more than $52 million for the company. Their bid recently received a shot in the arm when a judge in California ruled that Ackman can vote his own Allergan shares in favor of Valeant’s deal at a shareholder meeting next month.

While Ackman, Valeant and the Allergan board battle it out over the company’s fate, Allergan has seen its stock price skyrocket by about 75% since the beginning of the year. Clearly, the WSJ report that Ackman could view Zoetis as another candidate for a Valeant takeover has sparked investors’ interest in the company.

Zoetis is not far removed from being owned by a large drug company, as the maker of vaccines for pets and livestock was spun off by Pfizer (PFE) last year as part of a $2.2 billion initial public offering.

(UPDATE: A Zoetis spokesman provided Fortune with a statement acknowledging that Ackman called Zoetis to say that he made an investment in the company, but Zoetis is not commenting further on the details of that conversation. “We are preparing for our upcoming Investor Day on Tuesday, Nov. 18, and we look forward to sharing more details about the company’s business model and growth strategies with the investment community at that time,” the company said.)