Mon Feb 9, 2015 6:00pm EST

Drugmaker Pfizer Inc (PFE.N) said it entered into an agreement with Goldman, Sachs & Co to buy back $5 billion of its stock.

Pfizer said the accelerated share repurchase was assumed in the forecast for the full year it provided last month.

Under the agreement, which forms a part of Pfizer's existing buyback authorization, about 150 million shares will be bought.

The settlement is expected during or prior to the third quarter.

Shares of the New York-based company closed at $33.06 on the New York Stock Exchange on Monday.