As Greece shuts its banks and imposes capital controls, stressmeasures in financial markets show the threat of contagion islimited.

While Greek bank bonds tumbled and a credit-risk benchmark inEurope jumped, indicators of banking stress across the continentand in the U.S. suggest relative calm as concern mounts that Greecewill exit the euro. The U.S. two-year interest-rate swap spread, akey measure of risk for banks, rose Monday only to a high matchedlast week.

The relatively muted effect on markets reflects investors'confidence in firewalls erected to contain the fallout of apotential Greek default during months of debt talks. The EuropeanCentral Bank (ECB) has already been buying bonds under itsquantitative-easing program and has additional crisis tools putin place in the past few years.