After three months, H.R.H. Prince Mahisara concluded that the Book Club was performing well, with smooth cash flows in and out. In January 1905, the Club introduced cheque withdrawal services. Because it was run by Thais, it could provide Thai and Chinese customers with good services in their own languages and clear explanations of the account debit system. As a result, it attracted a large number of customers including merchants, businessmen, and public servants.
The average cash transactions increased rapidly, with the inflow of cash rising from about 50,000 bahtper month to 500,000 baht per month.
Cash outflows rose from about 50,000 baht to 300,000 baht per month. Four months after its opening, the balance sheet indicated that profits were satisfactory, implying that the Club was performing well. Buoyed by these successes, H.R.H. Prince Mahisara embarked into international trade, notably currency exchange, until then entirely controlled by the foreign bank branches.