A high-yield investment program (HYIP) is a type of Ponzi scheme, an investment scam that promises unsustainably high return on investment by paying previous investors with the money invested by new investors. Most of these scams work from anonymous offshore bases which make them hard to track down. All Ponzi/Hyips will fail. The later Investors will lose everything when the scheme folds and leaves with the Bitcoin. Most HYIPS and doublers etc, just steal it immediately. You send it and they keep it.
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From @kennyaliyus