100m sounds high but 100m is a rounding error especially if spread across 100s or even 1000s of trades.
I guess making 5% returns isn't such a big deal when you are playing with billions of other people's money.
Goldman Sachs will pay $5.06bn for its role in the 2008 financial crisis, the US Department of Justice said on Monday. The settlement, over the sale of mortgage-backed securities from 2005 to 2007, was first announced in January.
“This resolution holds Goldman Sachs accountable for its serious misconduct in falsely assuring investors that securities it sold were backed by sound mortgages, when it knew that they were full of mortgages that were likely to fail,” acting associate attorney general Stuart Delery said in a statement.
-- https://www.theguardian.com/business/2016/apr/11/goldman-sac...
In the, you know, "would you buy a used car from these guys?" sense.
I trust that you're aware of the basic chronology. If not, it should be fairly easy for you to look into.
If we had 20 large banks the size of GS, GS doing stupid shit and tanking wouldn't be an issue.