A customer has an account with ABC Brokerage and wants to transfer ownership of 300 shares of stock to his spouse who also has an account with ABC. This requires a(n)?

When a customer wants to transfer ownership of shares between accounts at the same brokerage, it is classified as an internal transfer. This involves moving assets from one account to another within the same financial institution without the need for external processes or transfers involving other brokerages.

In this scenario, since both the husband and wife hold their accounts with ABC Brokerage, the transfer of the 300 shares can be completed internally, simplifying the process with fewer regulatory hurdles and faster execution. An external transfer would involve moving the shares to a different brokerage, which is not necessary here. Similarly, the terms "full transfer" and "trade confirmation" do not accurately describe the nature of transferring shares between related accounts within the same brokerage. Therefore, the most appropriate term for this situation is an internal transfer.