BOC Hong Kong (Holdings) aims to increase earnings from its mainland business to 10 per cent of total group profit in the next three to five years. Pretax operating profit from its mainland operations almost doubled in the first six months of this year, credited to a 40 per cent increase in total loan volume to $15.13 billion. The mainland unit, which accounts for about 3 per cent of the group's business, is expected to take advantage of its parent company's extensive customer network to develop 'cross-border banking'. Many mainland companies that have established overseas headquarters in Hong Kong and bank with Bank of China naturally turn to BOCHK because of its unique relationship with their lender, vice-chairman and chief executive He Guangbei said. The bank posted interim net profit growth of 16.8 per cent to $6.52 billion, due largely to gains from property revaluation, assisted by healthy loan growth. Core earnings recorded reasonable growth with net interest income rising 6 per cent to $5.86 billion.