Earlier quoted context omitted.
What doesn't seem to be so explicitly stated is that due to rates going up, the bonds are worth less than they were when rates were high. So they wouldn't have enough money if they turned the bonds into money. Guy lends you 100 at 3%, you buy 100 of bonds than pay you 5%. Guy asks for his money back, your bonds are worth only 80, big problem.
One of the biggest banks in the world failed to account for a capital management risk scenario where interest rates go up? Insane
https://en.wikipedia.org/wiki/List_of_largest_banks
Not even amongst the largest banks in the US:
https://en.wikipedia.org/wiki/List_of_largest_banks_in_the_U...