You should be ready to write to the team about something you have to tell them. First of all, you don't have to disclose the bug to the team immediately but just have to inform them that you have something that could lead to them losing big money as a result of the bug.
They will be the one to ask you if what the big could be explaining in details. They might want to add bounty for you if your claim is genuine and could pose a big threat to them.