Australian Military Bank is a rare ADI with growth in loans for investment property purposes that exceeds APRA's ten per cent cap, a rule that has been in place now for around a year.Credit Union Australia, the largest mutual ADI in the country, last week opted to cut out all investment lending as its growth in this segment approached the APRA 'speed limit'.In common with smaller, often mutual ADIs, AMB's investment loan portfolio was small when the Australian Prudential Regulation Authority set the sector wide rule (announced in late 2014).John Ford, chief executive of Australian Military Bank, confirmed the breach to Banking Day this week.In a follow up email, Ford wrote that "in real terms our investor loan book has grown by approximately A$20 million since September 2015. "That's a growth rate of 20 per cent over a 17 month period and we have taken steps to decrease new flows by increasing pricing by 15 basis points and installing a maximum loan to valuation ratio of 80 per cent for new to bank borrowers."Ford pointed out the $20 million increase in the portfolio totals 70 home loans, representing an increase of around 4.2 investor home loans per month since September 2015."We are underweight in investor loans accounting for just 17 per cent of our mortgage portfolio. Importantly, we have a very low percentage of interest only loans accounting for just eight per cent of our entire home loan portfolio," he said. "The majority of our borrowers continue to be closely connected to our defence community bond and our mortgage arrears are well below industry standards. "We will, nonetheless, take on board APRA's latest macro-prudential controls," Ford concluded.