Answer
There's no standard, built-in mechanism specifically restricting who can see budget data — by default, any user connected to the relevant company via User Per Company can see that company's budget figures. If a specific restriction is genuinely needed, it has to be enforced as a custom restriction rather than a built-in setting: for a Lobby specifically, reference the user's Authority Class (or another distinguishing attribute you define) directly in the WHERE clause of the Lobby's Data Source Designer, so only users matching your defined authority see any data at all, while every other user sees nothing.