https://www.bitfinex.com/pages/howitworks#lendingLiquidity Providing
Our liquidity feature goes hand in hand with the margin trading feature described above. If you are not a trader and prefer safer investments, this feature is for you. Bitfinex allows you, using your deposit wallets, to provide liquidity in the form of Bitcoins and/or dollars to traders. You can enter offers with your own chosen terms (return rate, duration, and amount). When an offer is taken by a trader, the money in your wallet will be used to buy or sell Bitcoins, and a CFD (credit) will be opened. When the position expires (the trader closes his position), Bitcoins are bought or sold back and the money is returned to your wallet.
You are not exposed to exchange risk when you lend with Bitfinex. The exchange risk is taken on by the trader, and, in case his position loses money, he will cover the loss with funds in his trading wallet.
