On October 7th, Cinnobe's former cryptocurrency director Eric Wall said that nothing can stop Bitcoin owners from effectively expanding bitcoin supply. It may happen in the form of a bank, which holds a portfolio of assets, but can also issue loans without losing control. Wall believes that the use of Bitcoin may use a broad money supply, similar to the mix of central bank and commercial banking activities. Currently, most Bitcoin users tend to put Bitcoin in their wallet. But the management services for encrypted assets are expanding. Coinbase already offers a variety of managed wallets, and Bakkt also trades on a model that holds Bitcoin on behalf of customers. Wall warned that this is the first stage of using IOU (white bars) instead of using BTC directly. This use of bitcoin is equivalent to the exchange of cash in the bank vault for the promissory note.