Zoetis Inc. shares jumped Tuesday on a report that activist investor William Ackman has taken a stake in the animal health company and could push for its sale.

The company said that it did receive a call from Ackman indicating that the firm has made an investment in Zoetis. But Zoetis declined to comment on details of that conversation. Ackman’s firm Pershing Square Capital Management LP declined to comment.

Zoetis Inc. may share more details at its investor day next week, where it plans to discuss its business model and growth strategies.

The Florham Park, New Jersey makes medicines for pets and farm animals. It was formerly owned by drugmaker Pfizer Inc., which spun it off last year.

Shares of Zoetis increased 8.9 percent — its biggest-ever one-day jump — to close at $43.72 Tuesday and continued to rise after hours, adding 18 cents in extended trading.