Spanish healthcare company Grifols is close to a deal to buy Talecris Biotherapeutics, which produces plasma-based protein therapies, sources close to the proposed transaction said on Sunday.

The likely deal is expected to be over $3 billion in size, one of the sources said, adding it could be announced as early as Monday and is likely to be in cash and stock, with the majority in cash.

Talecris, which went public in October, was formed in 2005 when German drug and chemicals group Bayer sold its blood products unit to private equity firms Cerberus and Ampersand for $590 million.

The U.S. company had in 2008 agreed to merge with larger rival Australian blood products group CSL, but that deal was terminated last year under pressure from U.S. antitrust regulators.

Talecris has a market capitalization of nearly $2 billion, according to Reuters data. Its shares closed on Friday down 3.4% at $15.91. The Wall Street Journal earlier reported the deal was in the works and said that Cerberus and its co-investors could make a gain of more than $2 billion on their original investment.

Talecris and Grifols were not immediately available for comment. Cerberus declined to comment.