If you stop playing the game for over a month, your premium status will be terminated.
If you reached 500% or 1000% returns, your badges will be retained even if you do not hold premium status.
Every time your return goes over an additional 50%, you have to beat that return by another 50% to receive the prize. For example, if your return reaches 240%, then goes down to 97%, then back to 240%, you will not receive prizes for 100% to 200% returns. You will have to close over 250% in this case, because your last highest bonus return was 200%.