'Fun fact', that information wasn't on the FAQ 4.5 years ago and I figured it out the hard way. Wrote an e-mail to Cipsoft and they added it after that. Rip my 2.5kk :(
"Thank you for your request.
Your request has been forwarded to the responsible department for further evaluation.
Most likely we will include that information about the guild banks in the FAQ section with one of the next updates.
Thank you for your time and effort for bringing this to our attention and to help improve Tibia to make it a more fun and better place to be. We appreciate it.
Tibia Customer Support"