The text was extremely vague on the processes of supermassive black holes. After a little more research, it is clear that this field remains very speculative,although there are some intriguing possibilities.
Image Source: Wikimedia Commons
The most prevalent theory states that supermassive black holes are the product of the collision of primordial black holes. These black holes formed shortly after the Big Bang due to the extremely high pressures. Two black holes and their accompanying galaxies then would have collided, forming some sort of binary system pulling in matter from the surrounding space. This amount of mass would exceed any sort of pressure limits and form one supermassive black hole. This theory is often preferred due to the fact that it explains the relative lack of intermediate-mass black holes. There are many stellar-mass black holes, which form as a result of core collapse. These are on the order of 3-15 solar masses. There are also a high amount of supermassive black holes, which begin around 100,000 solar masses and increase from there. The gap in between the two suggests very different formation patterns, and not a continuous spectrum of constantly added mass that was once imagined.
Image Source: Wikimedia Commons
Astrophysicists have been able to model the collision theory, which lends even more support. But other theoretical explanations abound. The theory of accretion is the most plausible, where a core collapse black hole occurs in a high density region and then forms accretion disks to increase the mass. This theory helps conserve angular momentum, as transfer to gas particles can keep the black hole from spinning too fast and evaporating. However, this does not explain the lack of intermediate-mass black holes. The Laser Interferometer Space Antenna that will hopefully launch in the next twenty years should gather enough data to answer the question of supermassive black hole formation.
Sources and Further Reading:
http://en.wikipedia.org/wiki/Supermassive_black_hole#Formation
http://www.universetoday.com/104044/how-do-black-holes-get-super-massive/
http://www.wired.com/2010/08/massive-black-hole-origin/
