A technical team stayed in the Greek capital to work on details and negotiations will continue over the phone but it is unlikely that a deal can be clinched before a crucial meeting Monday of euro zone finance ministers, the sources said.
Following several rounds of talks from Wednesday to Friday, Greece and its private creditors, represented by Institute of International Finance chief Charles Dallara, are converging toward a deal in which private creditors will take a real loss of 65 to 70 percent.
The new bonds would feature 30-year maturity and a progressive interest rate averaging out at 4 percent, a banking official close to the talks told Reuters.
But a lot of details are still unresolved, and sources close to the negotiations said much of the attention will now turn to the euro zone finance ministers' meeting in Brussels, and to how EU paymaster Germany and the IMF view the progress in the debt swap talks.
"Discussions will continue over the phone this weekend but an agreement is unlikely before next week, if there is an agreement at all," one source close to the talks said. "Things are complicated, we are getting closer on the numbers but there is still quite some work ahead."
The IMF and EU countries, and in particular the bloc's paymaster Germany, want to make sure the deal puts Greece's derailed finances back on a sustainable track before they agree to a new, 130-billion-euro bailout, which is also crucial to avoid a messy default. How much money Athens needs from official lenders also depends on the details of the debt swap deal.
The IMF insists any deal must ensure Greece's debt burden will be cut to 120 percent of GDP by 2020 from 160 percent now, as agreed at an EU summit in October, and has warned that this is made more difficult by the fact that Athens' economic prospects have deteriorated since.
DEBT SUSTAINABILITY
A meeting Monday of euro zone finance ministers and the calculation of how the debt swap deal affects the sustainability of Greece's debt over the next decade will be key to any further progress in the talks.
"We will want to test the waters among member states because given the complex connections between private sector and official funding elements, we have to have the backing of member states for a deal," a senior EU source told Reuters.
A new analysis of Greece's debt sustainability could be ready before Monday's Eurogroup, or by mid-week, the source said, adding that a lot depended on how that was calculated. Long-term projections for Greece's economy, now in its fifth year of recession, will be key.
"The euro zone ministers will examine the proposal and say whether we have a deal. If they say we don't, we're back to the negotiating table," a banking source close to the talks said.
The IIF, which confirmed that Dallara and adviser Jean Lemierre had left Athens in the morning, repeated that the elements of the deal were coming into place and talks were continuing.
It said on Friday that now was the time "to act decisively and seize the opportunity to finalize this historic deal," a statement which seemed to be addressing Greece's official lenders, the EU and the IMF.
Haggling over the coupon had held up the long-running talks as Greece raced to wrap up an agreement, raising the prospect of a messy default when Athens faces 14.5 billion euros ($18.5 billion) of bond repayments in March.
A 15 percent cash sweetener will be made up of short-term bonds from Europe's temporary bailout fund, the European Financial Stability Facility (EFSF), two sources told Reuters.
"It will be near cash-equivalent short-term EFSF bonds," one of the sources said.
