Oil and gas company

Anadarko Petroleum

(APC) - Get Report

agreed to buy rival

Union Pacific Resources Group

(UPR)

for about $4.43 billion in stock.

Houston-based Anadarko will exchange 0.455 share for each Union Pacific share. That values Fort Worth, Texas-based Union Pacific at $17.60 a share, a 21% premium over Friday's closing price. Anadarko shareholders will control 53% of the stock of the combined company.

Anadarko expects to complete the purchase in July and said it will immediately boost earnings.

Robert Allison will remain Anadarko's chairman and chief executive. Union Pacific Chief Executive George Lindahl will become vice chairman of the combined company.

"This merger is an excellent fit for both companies," Allison said in a statement. "We blend Anadarko's strength's in exploration with what UPR does best -- profitable exploitation with industry-leading drilling and completion technology."

Union Pacific shares closed up 3/16, or 1%, at 14 11/16, while Anadarko shares closed down 4 3/16, or 11%, at 34 1/2.