The progressively gloomier prognostications over the extent of the accumulating bad debt load on Australian banks may need to take another turn for the worse, with new data shifting the spotlight away from big name borrowers towards signs of fast rising stress among the mass of middle market and smaller businesses.Debtor payments under credit insurance claims escalated over the first quarter of 2016, the NCI Trade Credit Risk Index shows.The NCI Trade Credit Risk Index is a periodic index produced by Adelaide-based insurance brokers NCI. The firm specialises in handling credit insurance and derives the index from its claims database.Over the first quarter of 2016, "credit insurance claims and adverse reports have dramatically increased," Kirk Cheesman, managing director of NCI, wrote in a short report yesterday.Cheesman said building, steel, retail and education "recorded large 'impact' insolvencies."He added that: "given the level of overdue reporting, a further runoff of insolvencies is predicted."The NCI index shows that insured trade payments considered as "serious overdues" is approaching the late 2008 peak recorded in the wake of the GFC.Claims are also near their post GFC peak, matching a recent high in the index over the summer of 2013/2014.Claims lodged over the March 2016 quarter "were up 80 per cent when compared with the first quarter of 2015," NCI said.The insurance broker said the advertising, building and hardware sectors "had the highest value of claims received."NCI's data will reinforce analysis being pushed by sell-side investments analysts of a sharp rise in the overall level of bad charges in the profit and loss statements of Australia's major banks. Three of these - Westpac, then ANZ and finally NAB - report for the half year to March 2016 during the first week of May.