|Quoting Bullpitt (Reply 2):|
Sometime luggage is never found, in my case BA lost mine and I never saw it again.
It may have been stolen. Baggage thefts by airport handling staff aren't unheard of. Only a small percentage of missing bags are never found. Sometimes they find bags with no identification inside or out (or it got torn off along with the baggage tag with passenger info/bar code etc). I think they also enter descriptions of those bags in the tracking systems and if lucky it might be matched up with the entry for a bag reported missing. That's why you should always include your name and contact info, including at the destination on that trip (with the dates you're going to be there) inside any checked bags, in case the tags on the outside (or the handle itself) gets torn off.
If it never shows up, after a certain period IB
should compensate you per their baggage liability rules (up to certain maximum limits and with various exceptions) as specified in their conditions of carriage. Any other compensation would depend on personal insurance you may have that covers such things. Many premium credit cards (Gold cards etc.) also include insurance coverage for lost/delayed baggage up to certain limits.