Yields on the Greek government’s brand new bonds are already trading at distressed debt levels — suggesting that despite February’s bailout package investors still see a strong chance that Greece will not be able to sustain even its much-reduced debt burden.

As the first week of trading closed, yields on the benchmark 10-years were at 18.24 percent — down from Tuesday’s closing high, but still the highest in the euro zone.

The new bonds have replaced old Greek paper, under a massive 206 billion ($273.5 billion) exchange program that swapped old bonds for new ones carrying lower coupons.

The high yields — the most elevated by far in the euro zone — reflect skepticism about whether the latest rescue deal, based on an orderly default of Greek debt, is enough to prevent a second default in the future. Last month private sector creditors reluctantly agreed to an effective default of 75 percent of the value of their debt, in a deal masterminded by euro zone finance ministers.