I asked a question recently about orbiting black holes. Thanks for the answers. So if I'm correct in my thinking, long before the event horizons of orbiting black holes become close to each other, the two accretion disks get mightily disrupted and much of the mass of the two disks would fall into the two black holes. Which got me thinking: What is the relative mass of a black hole singularity and its accretion disk? Is the singularity extremely more massive than the disk? Edits: I seem to be making some basic assumptions here, and I don't know if they are true. I seem to assume that there is some sort of mean proportion between black holes and their accretion disks. Is that true? Or is the mass of the disk only loosely related to the mass of the singularity? I'm also assuming that the limits and the demarcation of the accretion disk is well defined. Is this true? One could consider an entire galaxy to be the accretion disk of a supermassive black hole if one were to define it that way - but I assume that there exists a more precise and constrained definition? I'm also assuming that the respective masses can be well estimated. Is that true? Or does dark matter mess up any attempts at estimating the mass of the singularity and the disk?