This essay examines some aspects of overseas business of London Clearing Banks in the early twentieth century. It focuses on four matters. First, it provides pertinent facts regarding the overseas business of Martins Bank in 1911. Martins Bank was famous for its overseas business, which was a quite rare case among London Clearing Banks before World War I, but the activity has not known yet. Second, the great shortage of staff expert in overseas business is introduced and delineated. Some clearing banks founded overseas departments and some foreign banks opened London branches in the early twentieth century. This caused competition among the banks to recruit such staff and a struggle to train new staff. The lack of well trained staff limited the expansion of their overseas business. Third, this essay details the stock agency business carried out by clearing banks which intermediated between clients and stock brokers on small commissions. Consideration will be given to the extent to which banks lent their clients money to purchase overseas stocks. Fourth, the conventional view, which has insisted on the linkage between the increase in cash (gold) reserves and expansion of overseas business of clearing banks will be refuted. Based upon an examination of the constitution of cash reserves of Lloyds Bank, the second largest bank in UK in 1913, it will be demonstrated that the bank stocked sovereign gold coins adequate to satisfy the cash needs of small, day-to-day, domestic transactions.