Most common casinos accepting Investments: SafeDice, YoloDice, Crypto-Games.net, King Dice, MegaDice.
Maybe there is one or another accepting too, but these are the sites I know. Before start investing look for reviews about each one of them. When investing in casinos you need to always look for news, because few of them can go bad...
Just to add bitvest.io on that list they are accepting investment too.
And i know that you can invest in freebitcoin, they are giving 4% annual interest.
Yobit accepts, but it's not related to Dice game bankroll (At least not publicly). They say it's a tool for devs to promote their coins.
Check this thread for opinions about the service:
https://bitcointalk.org/index.php?topic=1922048.0Even promoting their exchange on my Signature I would be careful about this investment, as the rates are fixed and considerably high. They claim it's not a HYIP/Ponzi scheme, all we have is their word and so far it's working for everyone (sometimes they don't accept investments, when they can't afford to pay, so it's controlled and limited).
From where is that money coming from? Is it from them and i don't understand why they are sharing money unless it is some kind of hyip.