You mean that anyone who stakes on them, they get a share of about 30%? AFAIK with how the staking works on exchanges, they usually aren't that much and so if it's going to be around 5%-9% or even sometimes below those percentages, they're going to get a cut from the staker? it's possible since you're staking it on them and even before you receive the reward, they're getting a part of it because how will they earn from others fund? that's through getting a cut of it but I don't know how they do that and how much they take. Maybe, it's already out from the given percentage because it changes from time to time.