A surge in credit insurance claims may encourage a rethink on generally bullish views toward asset quality in banking.Claims on credit insurance climbed over the March 2017 quarter, with the demise of a host of building contractors one driver of a turnaround from a decline (against trend) over the December 2016 quarter.The Trade Credit Risk Index, produced by Adelaide-based insurance brokers NCI, is at an all-time high, and almost 50 per cent above a late 2015 low in the index. This has since been reversed by an 18-month long leap in claims.A staple item in each NCI report  is the "notable business failures this quarter" listing, and on this occasion the four insolvent businesses are all builders or contractors. The four are: Cullen Group Australia, PHP Contractors, Builtoncorp and WSH Group.When paired with a spike in the insolvency of trucking and other transport companies, a run of collapses in the building sector is a traditional lead indicator of a recession, or in any event a surge in the demands on workout teams at banks.Daniel Mackintosh, marketing coordinator, said there were only three claims for transport sector insolvencies in the database compiled by NCI to produce its index over the March quarter, a negligible number.Mackintosh said that at the other end of the scale, building and hardware produced 78 entries in NCI's index. Manufacturing fell second in this ranking for trade credit claims, followed by electrical, a sector closely aligned with building.NCI also reported a disproportionate level of trade insurance claims in Queensland, accounting for 38 per cent of the total.