Shueisha made a promotional article on V-Jump about the upcoming One Piece Magazine revealing some really interesting stuff. It seems to come directly from the editors, so it does appear to be canon:
The VJump article states Kaido is said to have a bounty of at least over 2 Billion Belly. Big Mom is also stated to have a bounty of at least over 2 Billion Belly. While some can argue that “Over 2 Billion” might mean just like Teach’s Bounty, but It’s probably above Teach’s. Also it does not say anywhere that it is under 3 Billion so it might be more. All it says is that “It is at least over 2 Billion”, and that was expected.
Shanks is implied to have the NUMBER ONE HIGHEST BOUNTY. He is immensely powerful and easily capable of fighting the Admirals, despite him having no devil fruit. He has also got connections to the Gorosei, which is how he was able to have a meeting with them.
- Big Mom and Kaido have bounties of at least 2 Billion.
- Shanks has the Highest Bounty among the Yonkou and might possibly have the highest in the series.
- Shanks does not have Devil Fruit.