Company officials said Monday they are not pursuing a merger with rival Humana, causing Cigna's stock to rise in the markets.

The courtship between insurance giants Cigna and Humana is just not meant to be, Cigna officials said Monday. Why it matters: The statement marks the likely end to on-and-off discussions about combining the companies into what would have been the nation's second-largest insurer — and potentially drawing antitrust scrutiny.