I work at a large bank. Mostly people hold all relevant knowledge in their own head, and when they receive a request for information they only respond if their manager knows yours. Then, they will mostly refuse to create any type of actual document and instead request that you set up a meeting with them through Outlook. They are of course completely booked on their Outlook calendar for at least the next few weeks, and then when you do get to talk to them they use obtuse department-specific acronyms as much as possible so that by the time you've started to understand the surface of their answer they have to leave for an urgent meeting.