How do very big companies manage passwords?


Third-party password managers such as 1password, etc. are very useful for people, businesses, etc. to store passwords, but obviously I bet Facebook, Google, Twitter and other super big tech companies don’t use such third-party services and have their own password managers for their most critical passwords.

How can a very big company manage some of the world’s most sensitive passwords? (example: Gmail team root access password!)

Even with the most advanced password manager, you still have the problem of the master password.

Should this be shared among a few trusted people? Or kept by only 1 or 2 people (then what happens in the case of an accident?)

Are big companies known to use implementations of Shamir’s Secret Sharing?

More generally, what are well known methods that very big companies use to manage their most sensitive passwords? (i.e. passwords that, if lost, could generate tens of billions of $ of loss)