[oooyay]

It's a half truth; the truth is somewhere in the middle of this and another theory. I'm not an economist, but the start of my professional life was marred by the experience of 2008 so I spent a lot of my time reading about it.

A source from the other side of this equation: https://www.cbsnews.com/news/heres-what-really-caused-housin...

In reality, there were a lot more sub-prime loans but only one of those lenders was actually expected to take on sub-prime loans. That's to say, taking on more sub-prime loans was a choice reflected in an ecosystem of incentives where profits were falling because a few lenders started a campaign to lower borrowing standards and the rest of the herd followed to stay afloat. What also happened was that lenders were essentially over weighting sub-prime loans into these packages and then using their relationships with the privately controlled ratings agencies to rate them the way that would be if they were filled with primes. If you read between the lines lenders found the solution to their profit problem and were trying to justify its stability post-hoc through package ratings. The reality is that sub-primes are highly profitable when they work out because they have high interest rates. When they don't they're not that expensive because generally the property is offloaded but this only works up to a magical threshold depending on a lot of risk variables. Once you go beyond that threshold and the dominos begin to fall, they all fall spectacularly. Risk traditionally should be leveled by packaging them with less risky loans.