...
... Hadn't heard ratings described as 'for sale' before.
this has all been adequately documented at this point. they were the key part of the fraud (see part 3)
1. the mortgage originators (e.g. Countrywide Financial) gave out mortgages to anyone with a pulse (and in a significant number of cases, even forged documents so unqualified buyers would qualify), and didn't perform any due diligence, such as verifying employment or income because they knew they weren't responsible for collecting the mortgage payments... that was a different party's responsibility, and therefore didn't bear the risk of bad underwriting practices, yet were allowed to keep all the underwriting fees!
2. then the banks (e.g. Goldman) took all the mortgages and bundled them into mortgage securities (MBEs), which are like bonds - the holder of the MBE collects all the mortgages payments from all the mortgages in the MBE, and resold them to third parties, typically pension funds, but also other banks (like Bear Stearns).
3. they were able to do this only because the rating agencies (e.g. Standard and Poors) rated all these MBEs AAA regardless of whether they were or not (and they were not) as pension funds were required by law to only buy AAA-rated securities.
4. a side issue that exacerbated this, AIG sold credit default swaps (CDS) essentially insurance policies that would pay out when the MBEs went broke (which occurred when enough people stopped paying their mortgages). AIG sold lots and lots of CDSs, without adequately providing reserves to pay them in the event the had to, giving a lot of the holders a false sense of security. it would be like Geico writing lots of auto-insurance policies for extremely risky drivers, without keeping cash reserves to pay on the claims.
all these problems were unnoticeable so long as people kept paying their mortgages. but they couldn't, either through job loss in a slowing economy, or because the adjustable rate mortgages they were given suddenly shot up in cost as the teaser rates the mortgage originators sold to them (remember from part 1 they played fast and loose with the issuing of these things).
when enough people started defaulting on their mortgages, all these obligations came due at once, and would've bankrupted the people holding MBEs and AIG, but the government stepped in to shore things up.
there are a lot of lawsuits flowing between these parties, but sadly, no criminal prosecutions for any of the people responsible despite all the outright evidence of fraud that has been presented.