BlockFi is a crypto-backed loan firm. What that means is that you can get a loan at a reasonable rate if you stake your crypto with them as collateral. They make the majority of their money off the interest from these loans.
On the investing end, you can deposit your crypto assets to your BlockFi account and earn up to 8.6% interest. As for how they can afford to pay that percentage, this is from their FAQ page:
What Does BlockFi Do with Account Assets?
BlockFi generates interest on assets held in Interest Accounts by lending them to trusted institutional and corporate borrowers. To ensure loan performance, BlockFi typically lends crypto on overcollateralized terms (similar to the structure of our crypto-backed loans). Furthermore, BlockFi’s automated risk management system monitors positions 24/7, leveraging the same trusted risk management system used with BlockFi’s crypto-backed loans. BlockFi has the ability to terminate a borrow in a timely fashion and also manages reserve balances to facilitate client withdrawals from Interest Accounts.
BlockFi client funds are structured to be at the top of the capital stack, senior to BlockFi equity and BlockFi employee capital. This means BlockFi’s business and client incentives are aligned and BlockFi would take a loss before any client would. BlockFi implements very thoughtful risk management practices and technology to mitigate the risk, but you should not view the BlockFi Interest Account as a savings account or brokerage account with FDIC or SIPC insurance.
As I stated earlier, there are a number of companies to choose from that offer this service, but Blockfi appears to be offering the best rates from what I’ve found.