Idk I thought it was revealed at MF because if they ahd known it was Ace wouldn't they have just killed him then? They went on a mass hunt for him rigth after Roger and even checked Portagas but she held Ace in and threw the scent off that trail. I think Ace always knew but not the Marines aside from Garp who protected him.
@bold we don't know a single thing about Ace's pirate career so the fact that you say he never attacked the WG directly is nothing more than speculation. Kidd had a higher bounty than Luffy and as far as we know he never attacked the WG directly, he attacked innocent villages and such, perhaps Ace was a bit of a **** in his start up piracy career before reaching WB, ever think of that. I saw someone else mention about the mention of the Mera Mera and the claim it got because of Ace. I don't recall what was word for word but it was along the lines of dozens of cities being burned to the ground when the addressed the Mera Mera No Mi(I guess at Dressrossa). The chapter is 702
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It implies Ace left quite a reputation with his MMnM.
Also the Marines don't know about his "alliance" which it's not actually at this point with Rayleigh, Son of Roger and Son of Dragon are comparable, Teamed with WB and a direct subordinate of WB are pretty much the same thing with Ace's connection actually being more significant of a point than Luffy, Luffy's actually allied with Boa, Jimbei and Law, and has beaten Moriah, Croc, Doffy and Buggy but the WG doesn't know about Hancock and are probably unsure about his invovlment with Jimbei all they really know thanks to the paper is he and Law are now allied. Also I thought the WG chose to hide that Luffy was invovled in ID thus his bounty isn't relfective of that though I could be wrong on that one.
This is the panel that made me think only Garp and the Fleet Admiral knew
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He says I'll tell them everything, sounds like no one or barely anyone else knew. The admirals may have known but it seems like only high ups knew, The shichibukai weren't kept in the loop and the admirals reactions are too straightfaced to know whether they knew or just know how to keep a straight face. But clearly the majority never knew and the world never knew so it'd be weird to base bounty on a detail the majority of the world knows nothing about.