New Zealand regional bank TSB Bank has reported a six per cent fall in annual net profit after it was forced to take losses on a loan to state-owned coal miner Solid Energy.TSB Bank said in its annual report that some of the bonds it held in Solid Energy had been converted to redeemable preference shares in a debt restructuring following the collapse of coking coal prices in 2012 that wiped out the miners' equity. It said it continued to hold Solid Energy bonds that were paying interest and was optimistic about the miner's future after the restructuring.TSB Bank reported a net profit for the year to March 31 of NZ$49.95 million, down from NZ$53.11 million the previous year, largely due to losses of NZ$11.5 million on bad loans, including to Solid Energy. Total lending rose seven per cent to NZ$4.53 billion, with residential mortgage lending rising four per cent and rural lending rising 56 per cent. Deposits rose 4.4 percent to NZ$5.15 billion.The bank's cost to income ratio was 39.16 per cent for the year and its tier one capital ratio fell to 13.91 per cent from 14.56 per cent a year earlier. Total capital fell to 14.21 per cent from 14.68 per cent, but is above the Reserve Bank's requirement for 10.5 per cent.The annual report also noted that Chairwoman Elaine Gill would retire from the board at its annual meeting in May. She has chaired the board since 1998.