Yeah, but look - I don't think there are investments large enough to break the 150 % even.
For example - If I pay 0.5 BTC and there are 10 other people with 0.05 BTC and this is the only money-source they have, I can't quite understand where they get their multiplied amount from.
Mining this much in just 10 days is pretty...well..hard I guess.
They might very well be trading, but it will only be a matter of time before they lose and can't make the payments or just decide to go away.