Amazon is bidding for all of the networks, including the YES Network, sources familiar said. Blackstone, a unknown sovereign wealth fund, along with the Yankees, are also bidding for the New York network.
Fox itself did not submit a bid in the first round for the networks although there's potential that it will join in the second round, the sources told CNBC. Earlier this year, Fox sold some television and movie assets to Disney, which owns the sports channel ESPN. The Justice Department forced Disney to sell the Fox regional sports networks to get that deal done.
Fox acquired its 80 percent interest in the YES Network in separate transactions in 2012 and 2014. YES is home to the New York Yankees and also carries Brooklyn Nets games.
The second round of bids is expected before year-end and due diligence on the bids begins next week. CNBC was unable to learn the amounts of the bids.
This is a developing story. Check back for updates.
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