Pfizer on Monday said it would complete the spinoff of its Zoetis animal health business after investors offered to trade their Pfizer shares for the company's remaining majority stake in the unit.

The drugmaker said it would distribute all its Zoetis Class A common stock, representing more than 80% of the animal health business, to investors who tendered Pfizer stock. Pfizer said it no longer would hold any ownership interest in Zoetis.

The exchange offer of 0.9898 Zoetis share for each Pfizer share expired on Friday. Pfizer will swap almost 401 million Zoetis shares for more than 405 million Pfizer shares. Pfizer said the exchange offer was oversubscribed, with almost 1.7 billion Pfizer shares tendered. It said it expects to complete the exchange on Wednesday.

With Zoetis fully divested, Pfizer said it expects full-year earnings, excluding special items, of $2.10 to $2.20 per share. It previously forecast $2.14 to $2.24. It projected 2013 revenue of $50.8 billion to $52.8 billion, down from an earlier forecast of $55.3 billion to $57.3 billion. It said its prior 2013 forecasts included revenue and earnings from its 80% stake in Zoetis.

Pfizer said the Zoetis spinoff will boost its earnings per share in 2014 because all 405 million Pfizer shares it is receiving for its Zoetis stake are considered retired.

Zoetis, in a separate statement, said it had named Michael McCallister, a company board member and former chief executive of managed care company Humana, as its non-executive board chairman. He will succeed Frank D'Amelio, Pfizer's chief financial officer. D'Amelio will remain a member of the Zoetis board.

Pfizer in February sold about 20% of its animal health business in an initial public offering of Zoetis that raised $2.2 billion. Pfizer continues to unload its non-pharmaceuticals businesses to focus on its core prescription drugs business, which has far higher profit margins.

In April 2012 Pfizer sold its infant nutrition business to Nestle for $11.9 billion.

The biggest U.S. drugmaker is also considering selling off its wide array of generic prescription drugs. In that event, it would keep its branded patent-protected medicines.