NEW YORK (AP) - Pfizer says the U.S. Federal Trade Commission has requested more information about its planned acquisition of rival drugmaker Allergan in a deal aimed at reducing Pfizer's tax bill.

NEW YORK (AP) Pfizer says the U.S. Federal Trade Commission has requested more information about its planned acquisition of rival drugmaker Allergan in a deal aimed at reducing Pfizer's tax bill.

Pfizer, the biggest U.S.-based drugmaker, said Wednesday the "second request" was expected as part of regulators' review.

The maker of Viagra says it continues to work cooperatively with the FTC. Pfizer still expects to complete the record $160 billion combination in the second half of 2016.

The deal, announced last November, would move Pfizer Inc.'s official headquarters for tax purposes from New York to Allergan's base in Ireland. The strategy, called a tax inversion, would sharply decrease Pfizer's income tax bill compared to current U.S. tax rates, though the drugmaker's operations would still be run from New York.