Fitch Ratings on Dec. 12 said it revised its BBB+ long-term issuer default ratings on 21st Century Fox Inc. and unit 21st Century Fox America Inc. to Rating Watch Positive from Rating Watch Negative.

The rating agency attributed the revision to the ongoing exchange offers by Walt Disney Co. for any and all outstanding notes issued by 21st Century Fox America for up to $18.1 billion of new notes in connection with Disney's deal to acquire certain 21st Century Fox assets.

Fitch said approximately $19.3 billion of debt outstanding as of Sept. 30 is affected by its action.