Forum:Luffy's New Bounty

Do you think Luffy's bounty will raise after breaking into Impel Down since the world governments keeping it a secret?

Also why didn't his bounty raise after defeating Moria? Even though they are keeping it a secret they kept secret about who defeated Crocodile but Luffy's bounty still went up.

I thought i read somewhere that the highest a bounty can be is 500 million. Is that true?