Abstract: The origin of supermassive black holes (SMBHs) is a key open question for contemporary astrophysics and cosmology. I review various formation scenarios for SMBHs and then discuss the predictions of the Pop III.1 model, i.e., seeding via metal-free stars forming in locally isolated dark matter minihalos, where dark matter annihilation has a chance to alter the structure of the star allowing growth to supermassive scales (Banik, Tan & Monaco 2019; Singh, Monaco & Tan 2023; Cammelli et al. 2025; Sanati et al. 2025a,b; Nandal et al. 2026; for a review see Tan et al. 2024 and this project page: https://cosmicorigins.space/smbh
The model predicts that all SMBHs form very early in the Universe (i.e., by z = 20) with a spatial distribution that is initially relatively unclustered. It also makes predictions for SMBH occupation fractions, host galaxy properties, frequency of binary SMBHs and the gravitational wave background. These predictions are compared to latest results from the Hubble Space Telescope, James Webb Spact Telescope and pulsar timing array observations. Another key prediction is an early phase of “flash” ionization of the universe at z~20, which can help alleviate cosmological tensions (Hubble tension, dynamical dark energy, negative neutrino masses) (Tan 2025; Tan & Komatsu 2026; Aggarwal et al. 2026). Finally, since the Pop III.1 mechanism relies on the process of WIMP dark matter self-annihilation, there are implication for the nature of the dark matter particle.