If a bank's required reserves increase due to a rise in the reserve requirement ratio, the bank must adjust its T-account by decreasing its total assets to maintain balance.

When a bank's required reserves increase because the reserve requirement ratio goes up, it means the bank has to keep more money in reserve and cannot lend out as much. A T-account helps us see the bank's financial position, showing assets on one side and liabilities on the other. To keep everything balanced, if the required reserves go up, the bank needs to decrease its total assets, which could mean reducing loans or selling off some investments. For example, if a bank has to hold an extra $100,000 in reserves, it might reduce its loans by that same amount to ensure its T-account stays balanced. This adjustment is crucial because it helps the bank meet regulatory requirements while managing its overall financial health.