Strong growth in assets and revenue was not reflected in Bank Australia's bottom line in the 2015/16 financial year, as it ramped up its investment spend.Bank Australia reported net profit of A$22.6 million for the year to June - down 5.7 per cent on the previous year.The net interest margin fell 10 basis points to 2.11 per cent.Assets grew 12.8 per cent to $4.04 billion and net interest revenue grew 6.4 per cent to $80.5 million.Bank Australia managing director Damien Walsh said the bank made a decision to forgo profit and invest in the brand and technology.Walsh said it was a good decision: "We achieved deposit and loan growth both well above system, which is pleasing in the current low interest rate and competitive environment."Deposits were up 12.5 per cent to $3.4 billion and the value of loans funded rose 45.9 per cent to $1.08 billion.Walsh said the bank had a strong capital adequacy ratio of 18.7 per cent and was in a position to continue with its growth.He said the investment in digital services was necessary to attract young customers. The bank was successful in this, with the average age of customers falling during the year.