Greek default is essentially a given: S&P

NEW YORK (CNNMoney) -- Greece will eventually default on its debts, even if the nation reaches a deal with the private sector to restructure its debts, according to a panel of experts.

John Chambers, head of sovereign ratings at Standard & Poor's, said Tuesday that the deal being negotiated between Greece and private sector investors would "in all likelihood" qualify as a default.

The proposed restructuring aims to reduce Greece's debt load to 120% of its economic output by 2020, from 160% currently.

But even at that level, Greece's debt burden would still be "very high" and the nation's credit rating will remain "very low," said Chambers.

CNN