What happens when somebody has more than a million containers? 6 digits doesn't seem enough to guarantee uniqueness.
* https://www.bic-code.org/bic-company-search/?searchterm=MAER...
Huh, that's a lot less than I expected there to be.
I would guess that the next answer is "Evergreen gets multiple Owner codes", because that's a real simple way to stretch it, but...
This was their source. Apparently not updated since that 2012 survey: https://www.csiu.co/resources-and-links/world-container-flee...
You can read more about the container numbering standard here: https://en.wikipedia.org/wiki/ISO_6346