Some delegation services propose to also participate to a bond pool rather than just the usual delegation. How is that different? Is it safe?
In short the answer has to do with
1) what is called counterparty risk
2) and how much is at risk.
In Tezos, regular delegation does not put your capital at risk because your xtz never leave your wallet while you allow the baker to vote on your behalf and get baking rights thanks to your delegation. The baker collects the baking rewards and then distributes those (less a fee they set) to their delegees. Since the distribution of baking rewards is not controlled by the protocol itself this is the responsibility of the baker to do so. For this reason there is counterparty risk to the baker but only for the amount of baking reward (interest) that you are due, not the principal.
Bond pool is very different. In bond pool one transfers an actual amount of capital to the baker. The rationale is to help the baker increase his ability to increase the baking bond so that he can in turn get more rights to bake more by accepting more delegates. But financially it is a regular loan, not controlled by the tezos protocol, so the counterparty risk to the baker is much higher since the principal is also at risk, not just the interest. They will generally offer a bit higher rewards in compensation but this is a very different amount of capital at risk!
A bond pool, or Staking as a Service (by some definitions), is a technique for a delegation service to increase the size of its bond wallet in order to support a larger staking balance as provided by delegators.
While a delegation service can theoretically attract an unlimited amount of staking rights from delegators (only bounded by the total amount of Tezos in circulation), that delegation service can only deliver rewards for the rights for which it has enough bond to cover the deposits required each cycle.
In some cases, delegation services become significantly overweighted with staking rights, and if the service can not secure enough XTZ in its bond wallet at the particular time when needed, an imbalance called "over-delegation" will occur with the result being fewer rewards than maximally available.
Being over delegated creates a black mark on the perception of that delegation service (as services like Bakendorse.com and MyTezosBaker.com track and report on baking efficiency). Since the delegator can not effectively control on-chain the number of XTZs delegated to them, they will attempt other strategies to keep from being over-delegated.
Foremost, a delegation service will attempt to acquire more XTZ with house funds. But that may not always be feasible. So the delegation service may implement a bond pool to utilize the holdings of other large XTZ holders who may not be using their XTZ for baking.
While there are nuances between different bakers' bond pools, the central tenants are:
- A pool member transfers XTZ to the delegation service bond wallet.
- Those XTZs are used for bond across one or more cycles.
- The pool member will receive rewards that are commensurate with their share of the overall bond pool.
- Bond pool members may be contractually obligated to hold their XTZ in the pool for a specific time period before they are eligible for redemption.
Successful bond pools that operate with an optimal ratio of staking rights and bond, can generate significantly higher rewards for the pool member. Tezos Capital (my service) for example reports bond pool rewards of 12.55% over the period of cycles 61-70, while our standard delegator returns were 7.33% over the same period.
From a risk perspective, participating in a bond pool does require the transfer of XTZs to a wallet you no longer directly control. This may be akin to keeping tokens on an exchange. Knowing your delegation service, reviewing their performance over a sufficient timeframe, and doing independent research are all recommended steps if you choose to pursue participation in a bond pool.