Over-delegation and self-bond requirements for bakers and delegators
Almost all websites^(1) that rank bakers currently assume a self-bond requirement of 8.25% and decide whether a specific baker is over-delegated or not based on that.
**However the self-bond requirement of 8.25% that everyone currently assumes doesn't apply yet and most decisions on over-delegation are currently simply wrong.**
Instead of just leaving you hanging and claiming that I have now idea what I am talking about I'll explain the formula and how to calculate whether someone is over-delegated or not.
# How self-bond requirements are calculated
The rational of the economic and security model of Tezos states that at least 8.25% has to be slashable and at risk. There are two other variables which influence this number - *"time"* and *"percentage of total supply staked"*.
8.25% only applies after cycle 64, which is about 6 months after launch. Until cycle 64 it scales linearly from cycle 0. This means that at cycle 0 the self-bond requirement was 0.0% and every further cycle adds another 0.1375%. For example, at cycle 11, the self-bond requirement is 1.51% (0.1375\*11).
Furthermore, it is only 8.25% if 100% of the total XTZ supply are staked. The amount of staked XTZ is calculated by adding self-bonded and delegated XTZ. You can see the total amount of staked XTZ [here](https://tzscan.io/rolls-distribution) and caculate it by multiplying the number of rolls by 10,000, since it's 10k XTZ per roll. The total supply is 763,306,930 XTZ. If less than the total supply is staked than this linearly increases the self-bond requirement. For example, if 50% of XTZ is staked, the self-bond requirement is 16.5% (8.25/0.5). For the current cycle 11 the staked percentage is \~36% (278,360,000/763,306,930).
# Practical example with our baker, Cryptium Labs
**This can be seen as a shameless plug and it sort of is, but really I just wanted a concrete example.** Chris, Awa and I are running Cryptium Labs, which is a PoS validator, and hence baker, based fully in Switzerland....
The Tezos Foundation is pleased to announce that it has issued a grant to OCamlPro to support its work on TzScan, a block explorer for the Tezos blockchain that will be made open-source. OCamlPro is a...