The major banks, or the value of their share prices at least, "are in a fragile equilibrium," the industry analysts at Morgan Stanley Australia argue in a report released this week.Richard Wiles and Andrei Stadnik write that "the banks are in a fragile equilibrium.""We see a number of challenges on the horizon for Australian banks," the report says, listing an extension of the deposit margin squeeze, while "further home loan re-pricing risks slowing loan growth."The report says "higher debt levels, higher house prices and tighter lending standards increase risks in the housing market."Wiles and Stadnik are also sanguine of macroeconomic factors, pointing to "weak income and employment trends weighing on the outlook for the economy and credit quality," while "the nation's AAA and the banks' AA credit ratings are under review."Also potent: "APRA's new capital rules are due in coming months [while] ongoing scrutiny of pricing and conduct is likely," and, indeed, in action today as ANZ and CommBank executives front the House of Representatives Standing Committee on Economics.    The equity market's "fragile equilibrium" on banks, the Morgan Stanley team theorise, prices and investors have supported loan growth; home loan re-pricing is "at risk of breaking", with the sector "priced for a sweet spot", given its is trading on a one-year forward price to earnings multiple of around 13.5 ties. This, they say, "is one standard deviation above the post 2010 average of around 12 times, based on consensus estimates.""At the same time, they don't look cheap on any other measure."