It seems to me that the 'global finance system' is like a big stack of software entities, all interacting with each other, all written by different people and at different times, and with new patches applied often. No one can figure out the big picture of the whole system, but they have theories about parts of it. For a long time it has seemed to work and all hang together. Hackers and viruses exploit loopholes as they find them.
Then, about a year ago, we hit a blue screen of death. The illusion that the system was self-repairing was lost.
We managed to reboot in safe mode, but we're not sure when we'll hit the next big bug.
(and although this is meant as metaphor, bear in mind that large parts of the global finance system literally are software entities these days)