Vegas World's Sports Book now limits the total Coins that can be wagered on each event. The max bet per event is 3% of your current Coin total up to a maximum of 10,000,000,000 Coins. Once the Coin maximum has been placed on a game or event, no further wagers on that same game or event will be accepted. Multiple wagers on each game/event are possible, up to the maximum.
The quickest way to make the max bet is to slide the slider bar marker all the way to the right, until it rests above where it says "MAX". That'll set you up with the biggest possible wager for your account.