The question is pretty self-explanatory. I'd like to know, who in the One-piece world has the max bounty declared against them till date? Note that the bounty amount has to be mentioned in either anime or manga or in the movies. I am assuming it is Katakuri? But I'm not sure.
The current highest active bounty is that of Charlotte Katakuri, one of the Three Sweet Commanders of Yonko Big Mom with a bounty of 1,057,000,000.
Taken from One Piece Wikia. One Piece Manga — Vol. 86 Chapter 860 (p. 14) is given as reference.