TSB Bank's continued focus on raising funds via retail deposits and lending conservatively means the bank hasn't maximised its profits.Net profit for the June 2010 quarter came in at NZ$8.7 million, down from NZ$14.9 million in the same quarter a year earlier and compared with NZ$51.8 million for the full year ending March 2010. The profit included a deferred tax adjustment of NZ$4 million that takes into account zero per cent depreciation that will be applicable from next income year to buildings with a life of over 50 years. TSB earned just NZ$20.9 million as interest in investment securities, which was half of the NZ$41.3 million earned from loans to customers. The quarter saw a small rise in TSB's loan book and deposits. The bank increased its mortgages to NZ$2.2 billion, up just NZ$56 million from March. Deposits grew just NZ$25 million from March to NZ$4.0 billion.The only silver lining for the bank is that the deposit growth during the quarter was fully invested in loans, as investment in securities remained steady during the June quarter.