Aetna Inc’s (AET.N) chief executive said Monday he was confident any antitrust review of the health insurer’s proposed purchase of smaller rival Humana Inc (HUM.N) would allow the deal to close in the second half of 2016. Mark Bertolini said Aetna had already prepared for possible divestitures to address overlaps with Humana’s business in the largest-ever U.S. health insurance deal. Aetna has not discussed the deal directly with the U.S. Department of Justice, but has consulted with regulatory experts, Bertolini told cable channel CNBC.