(AOF) – Oil producer APA and Callon Petroleum Company (an independent American oil and gas company based in Houston) have entered into a definitive agreement. APA will acquire Callon in an all-stock transaction valued at approximately $4.5 billion. Under the terms of the transaction, each Callon common share will be exchanged for a fixed ratio of 1.0425 APA common shares. Callon’s assets will strengthen APA’s activities in the Permian Basin (in Texas), increasing its surface area by 50%.