Deutsche Bank is counterparty to 55 trillion euros of derivatives contracts (about 65 trillion USD). I worked for 3 years on its trading floor. It was Sales-a-gogo. "Print as much as you can". It's one of the very biggest counterparties to derivatives. Imagine if there was basis risk of only one tenth of one percent on those books (ie hedge imperfection usually due to a third factor such as credit quality or geograph…
Only partially related, I remember one of the German landsbanke (can't remember its name) buying full one-page splashy ads in magazines like The Economist, back in 2007. Only one year later they went catastrophically under because they had bought in into the subprime lending and its derivatives' mania. I remember one of the directors saying something like "we didn't know what exactly we were buying, those products were too complicated for us, we trusted the people who had sold them to us". It's fools all the way down.