There is a little risk, but you can lend for 2 or 60 days max. It ussually gaves 0.10% but because of speculation about aug 1st is giving like 4% daily return. there is no way to it to not be payed, because that money is used for margin trading.

I have been lending in poloniex for 2 months, it really works.

The lowest loan offer right now is 3.1%.

The risks to loaning on POLO are listed below.
a) A flash crash happens and the POLO program doesn't call the margin in time for the loan taker to pay you back.
b) Polo's program has an error and you do not get your funds back,
c)Your Polo account gets hacked, and someone manages to steal you coins when they are not on order.
d)Polo becomes insolvent due to coins getting hacked/embezzeled/seized.