The vulnerability of a casualised workforce is one risk highlighted in an analysis of banks' sensitivities to shocks and pressure on credit profiles circulated by Moody's Investors Service yesterday.Moody's pointed to "rising underemployment, which is now much higher than the long-run average dating back to the 1990/91 recession, suggesting excess capacity in the labour market and continued pressure on wage prospects in the future."The credit ratings agency said this development had "the potential to stretch household finances further and reduce household financial flexibility. Households could therefore become more vulnerable to a change in financial and asset market conditions."It said that, while low interest rates were currently supporting the debt servicing capability of borrowers, it viewed "the combination of low wage growth, high household leverage, and rising property prices to be increasing tail risks for Australian banks."Moody's explained that "income trends are posing increasing challenges.""While the Australian economy has continued to deliver growth in real GDP terms, key measures of national income have been deteriorating. The terms of trade shock - experienced as a result of the precipitous fall in commodity prices through 2015 - has significantly constrained the growth in nominal GDP and real net disposable income."Moody's also pointed to "house prices risk diverging further from income fundamentals. The search for safe investment assets offering capital growth, combined with capital inflows from overseas, have led to an increase in investor activity and sustained house price appreciation in the major cities."This development has led to a growing disconnect between local housing prices and household incomes, increasing household leverage to an all-time high." The "headwinds" cited by Moody's in its report may, it said, "over time, put pressure on the credit profiles of Australia's major banks, particularly in the context of their very high ratings."