On Zai Options there's a weekly ZAIF jackpot that accumulates every week, after approx. 200480 blocks the jackpot accumulated will be added to the round prize pool, the Zai options page shows which block the jackpot will be paid, the winning side of that round will get the jackpot amount divided by the number of players + the round amount.
So basically on every "Jackpot Round" the bettors´ amount will be leveraged.
The jackpot accumulates on every claim of users who doesn't have a referrer, 2% of the user winning amount will be put into the jackpot.
If the jackpot round is canceled, the amount accumulated will accumulate to the next week´s pot.