CUA's big investment program put the brakes on earnings growth in the December half-year. Australia's biggest credit union yesterday reported a net profit of A$24.6 million for the half - down 5.5 per cent on the previous corresponding period.Interest revenue increased by 18.6 per cent during the half, but expenses were up 20.9 per cent. CUA is installing a new core banking system as well as new electronic banking systems.It hired about 100 new people during the half.Loan settlements fell by 33.8 per cent during the half-year. CUA chief executive Chris Whitehead said in a statement that this was due to "a downturn in consumer confidence and softer than expected economic conditions."Total assets (mostly mortgages but also including personal and business loans) increased by two per cent to $9.01 billion. Retail deposits were up 6.2 per cent to $6.4 billion.Whitehead said CUA would continue to produce flat profit results for the medium term while it completed its investment program.