Realistic Loan Demand for Banks has been improved in version 9.1.04.
Realistic Loan Demand for Banks
If this option is enabled, the demand for bank loans is realistically based on the total GDP of the cities. If this is disabled, the loan demand will be substantially higher but still have a limit. (In the previous versions, there is no limit if this option is disabled.)
This adjustment improves gameplay balance because consistently high loan demand can lead to excessively huge bank profits after the game has been running for a very long time.