If accepted by all the holdouts, which are led by US billionaire Paul Singer's Elliott Management, the deal will clear the way for Argentina's return to the international capital markets, providing a boost for the stagnant and inflation-wracked economy long starved of foreign investment.
"The proposal by Argentina is a historic breakthrough," said mediator Daniel Pollack. He said any deal would be subject to approval by Argentina's congress and the lifting of an injunction issued by New York judge Thomas Griesa.
Mr Pollack said four of the six leading holdouts had yet to reach an agreement, but that it was his "strong hope that, with continued negotiations, those firms, too, will be able to resolve their differences and reach Agreements in Principle with Argentina".
"The events of this week and today were an important step in resolving Argentina's debt crisis; more remains to be done," he added, referring to "intense but civil" negotiations between Argentina and the holdouts since Monday.