All cryptoassets are stored in offline, cold, multi-signature wallets.
Transaction signing only happens offline on separate devices that have never been connected to the network, and this process involves several people.
The multi-signature process involves several keys (N) with a required quorum of any (M) keys. For example, you need 3 out of 5 keys or 5 out of 8 keys to conduct a transaction. Thus, it’s not possible to sign the transaction using a single individual. Also, this system ensures that, if you lose one of the multi-sig keys, you will never lose control over your assets completely.
We store encrypted parts of the keys in a geographically-distributed manner in the banks’ safe deposit boxes to prevent potential loss of the keys due to natural disasters, including floods, earthquakes, fires, etc.