This hole is claimed to have attained about 10% of its host galaxy's mass, when universe was only 2 Gyr old, as opposed to usual story which is attaining 0.2% to 0.5% of galaxy mass by now (universe age 13.8 Gyr). How? Benny Trakhtenbrot, C. Megan Urry, 7 others: An over-massive black hole in a typical star-forming galaxy, 2 billion years after the Big Bang Science 349, 6244 (10 July 2015) 168-171 ABSTRACT Supermassive black holes (SMBHs) and their host galaxies are generally thought to coevolve, so that the SMBH achieves up to about 0.2 to 0.5% of the host galaxy mass in the present day. The radiation emitted from the growing SMBH is expected to affect star formation throughout the host galaxy. The relevance of this scenario at early cosmic epochs is not yet established. We present spectroscopic observations of a galaxy at redshift z=3.328, which hosts an actively accreting, extremely massive BH, in its final stages of growth. The SMBH mass is roughly one-tenth the mass of the entire host galaxy, suggesting that it has grown much more efficiently than the host, contrary to models of synchronized coevolution. The host galaxy is forming stars at an intense rate, despite the presence of a SMBH-driven gas outflow.