The husband and wife already own the NHL's Buffalo Sabres. Longtime Bills owner Ralph Wilson died in March, prompting the sale.
The Pegulas offered $1.4 billion to buy the NFL franchise. Buffalo sports fans were concerned the team could be moved out of state if purchased by another group.
Kim Pegula is expected to have a high-ranking role with the Bills, working alongside current team president Russ Brandon.
Terry Pegula has a net worth valued of over $3.5 billion, and made his fortune in the natural gas industry. In 2010, he completed a deal to sell a large portion of his company East Resources' assets for $4.7 billion to Royal Dutch Shell.
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