Drugmakers Pfizer and Wyeth are close to sealing a deal worth $68 billion in a cash-and-stock deal that could be announced before the markets open Monday, according to reports.

The Wall Street Journal, citing people familiar with the matter, reported Sunday evening that Pfizer, the world's largest drug maker, is working to finish financing for the acquisition.

Pfizer is expected to offer Wyeth shareholders $50.19 per share, paying $33 a share in cash and 0.985 a share in Pfizer stock, according to the sources.

That would be a 29 percent premium over where the shares closed on Thursday before the Journal reported that the two were in talks.

According to the research firm Capital IQ, it would be the biggest merger in the U.S. in nearly three years since AT&T and BellSouth combined in a $70 billion deal in March 2006.

The deal would increase Pfizer's revenue by half and will add strength in biotech drugs, vaccines and over-the-counter products, including the Advil and Robitussin brands.