https://www.bis.org/publ/work269.htm

>> In fact, the true causal relationship actually runs in exactly the opposite direction.
>>The banking system creates deposits as they are demanded by the private sector,
and the central bank’s main liquidity management task is to ensure a sufficient supply of balances for the system as a whole to maintain reserve requirements, if any, associated with those deposits.

>>It is the amount of deposits that the banking sector can attract that determines the level of reserves not the other way around.