A good investiment in my opinion would be casino bankroll. If you invest $20.000 on it (28 BTCs), you can earn 4.48 BTC monthly income... I don't know if the casino limits a max investiment allowed. And it's not guaranteed, I'm considering you can make 16% profit monthly, but it surely can change. Tell what do you think.
If at all if i am investing in a casino how could i be sure that i will be guaranteed the return if the casino is at a loss,since there are many hacks in most of the online casinos and in that case how can i trust my investment with it.