Australia's biggest credit union, CUA, has completed development of a new core banking system and will start to update services in the second half of the year.CUA's chief executive, Chris Whitehead, said the new system was undergoing several months of testing. An updated mobile banking platform and a new internet banking site are on the drawing board for later in the year.Yesterday, CUA reported net profit of A$34.1 million for the six months to December - up 38.6 per cent on the previous corresponding period. Interest income rose 3.9 per cent. Whitehead said the big jump in earnings was the result of growth in other revenue and tight cost management.Retail deposits increased 7.9 per cent to $6.9 billion.The number of new loans settled increased by 41.2 per cent. Whitehead said the credit union's Rate Breaker home loan (whose rate is set at 100 basis points below the average standard variable rate of the big four banks) has been very popular.CUA has also been aggressive in setting fixed mortgage rates. Currently it is offering 5.1 per cent for three years.CUA has traditionally sold a lot of fixed-rate mortgages, which make up as much as 50 per cent of its book. Whitehead said Rate Breaker, which was launched in June last year, has helped it pick up share in the variable rate segment of the market."Our 12-month rolling average growth rate [in home loans] for the year to December was nine per cent, compared with 4.5 per cent for the market," he said.CUA's capital adequacy ratio remained constant at 14.7 per cent. Standard & Poor's raised its rating from BBB to BBB+.