Watson Pharmaceuticals Inc. (NYSE: WPI) will announce on Wednesday the purchase of major Swiss competitor Actavis Group, according to media reports citing persons familiar with the negotiations.

The deal, valued at €4.5 billion ($5.92 billion), will elevate Parsippany, N.J.-based Watson to one of the world's top generic-drugs makers and allow it to surpass its primary U.S. competitor, Mylan Inc. (Nasdaq: MYL), the Wall Street Journal reported Tuesday.

Watson's stock price was down $1.60, or 2.29 percent, to $67.86 in afternoon trading.

The move shows Watson's efforts to aggressively expand its global share of the generic drugs market. The company was the fourth-largest generic-drug maker in the U.S. in 2010, based on sales, according to FiercePharma. Its 29 percent increase in net revenue last year elevated the company to No. 3.

Watson's generic drugs unit registered $3.37 billion in net revenue, up 44 percent from the previous year, according to the company's 2011 annual report. However, only $501 million of that revenue, or about 15 percent, was international.

Watson makes generic versions Concerta, which treats attention deficit disorders, the anti-cholesterol brand Lipitor and Kadian, an extended-release morphine capsule.

The deal will mean the only two generic drug makers that will be larger than Watson will be Israel's Teva Pharmaceutical Industries Ltd. (TLV: TEVA) and Sandoz, a unit of Switzerland's Novartis AG (Nasdaq: NVS).

The move was welcomed by Watson investors and could lead to a reduction in Watson's U.S.-based manufacturing, according to Reuters.

Deutsche Bank is Actavis Group's primary lender and the deal is expected to be announced before the bank's first-quarter results on Thursday, the Financial Times reported. The bank holds billions of euros of the company's debt following a leverage buyout in 2007 resulting from the global economic crisis.