Banks will want to hold more excess reserves, everything else equal, when (a) it expects to have deposit inflows in the near future.
When a bank anticipates an increase in deposits, it aims to maintain sufficient liquidity to manage these inflows effectively. This approach helps the bank prepare for potential withdrawal demands from customers while having the ability to capitalize on new lending opportunities that might arise from these additional funds. Holding excess reserves in this context serves as a buffer, providing the bank with a cushion that supports operational stability and satisfies regulatory requirements.