as far as I know, the longest running HYIP was Hashocean and now it is gone. based on my experiences and avice from the people here, stop investing on HYIP, PONZI, DOUBLER and MINING. try to learn about trading. it will give you a good bitcoin
Agree, trading is one of the best methods to grow your bitcoins. But make sure that before you go and trade, please do some good diligence and do your homework first otherwise, you will end up with nothing. Trading is a double-edged sword, it can do harm and good for you - just learn how to use it and you are good to go.
Just follow this principle: If it is too good to be true, it must not be true