SM Energy and Civitas Resources announced an all-stock merger valued at about $2.8 billion in equity, or $12.8 billion including debt, creating one of the largest independent U.S. shale producers by output and acreage. Bloomberg reported that under the agreement, Civitas shareholders will receive 1.45 shares of SM Energy for each share of Civitas they own, giving Civitas investors about 52% of the combined company and SM shareholders 48%. According to Reuters, the combined firm will operate under the SM Energy name and be headquartered in…