Final answer:
Depositing $1 million into a checking account increases the bank's reserves correspondingly while the total reserves in the banking system remain unchanged, since the deposited funds are transferred from the individual's possession to the bank's reserve.
Step-by-step explanation:
When Bash deposits $1 million into his checking account, the banking system sees an increase in its reserves by that same amount. This is due to the fact that banks are required to hold a portion of deposits as reserves. These reserves are used to meet withdrawal demands and are regulated by the Federal Reserve. The money that is not held as required reserves can be loaned out by the bank to other borrowers.
This process increases the M1 money supply, which consists of physical currency in the hands of the public and checkable deposits. Depositing money into a bank increases the bank's reserves, but does not change the total reserves in the banking system immediately as the reserves simply shift from being held by individuals to being held by the bank. Since the question specifies that everything else is held constant, we can assume that the bank's required reserves proportion hasn't changed and that the increase in deposits directly translates into an increase in total reserves.