(Fortune) -- European finance chiefs said Sunday that Greece could receive aid of as much as 30 billion euros ($40 billion) at a 5% interest rate.
EU leaders haven't yet agreed unanimously to offer Greece a bailout, but the European Commission said it would start working on a plan Monday in conjunction with the European Central Bank, Greek authorities and the International Monetary Fund.
Finance ministers made the terms of the potential deal public in an effort to reassure world financial markets, which have been unnerved by Greece's debt woes for months.
According to the Associated Press, the IMF is prepared to lend Greece 10 billion euros. IMF managing director Dominique Strauss-Kahn said the organization was ready to help in any way "needed and requested by the Greek authorities."
The news of a concrete plan to help the country comes ahead of a major offering of Greek treasurys set for Tuesday, the results of which should illustrate either that Greece can raise its own funds, or that it must be rescued.
But the particulars of any bailout have been scarce until now, despite the fact that instability in Greece first became apparent in mid-February.
Last month the EU and the IMF both pledged to provide support for Greece as needed. But because the terms of the package weren't fully explained, the promises have carried little weight with bondholders, who remain fearful that Greece will buckle under the weight of enormous debts and default.
Sunday's news added clarity that could assuage those concerns.
"This storm isn't going to pass," until we see "a nice, big, round number," said Jan Randolph, director of sovereign risk country management at forecaster IHS Global Insight in London.
The Greek fears recall Henry Paulson's harried weekends as Treasury secretary in 2008, which brought the Bear Stearns bailout, the failure of Lehman Brothers and two months of haggling over the U.S. mortgage giants Fannie Mae (FNM, Fortune 500) and Freddie Mac (FRE, Fortune 500).
Early on in that saga, Paulson asked Congress for a huge Treasury credit line to help Fannie and Freddie, hoping the pledge of support would make an actual showdown with the bond market unlikely.
"If you've got a squirt gun in your pocket, you may have to take it out," Paulson said at the time. "If you've got a bazooka and people know you've got it, you may not have to take it out."
He miscalculated and two months later, investor flight prompted the government to seize Fannie and Freddie.
Interest rates on Greek government bonds have soared this week. Greece needs to borrow 30 billion euros ($40 billion) between now and the end of June to pay down maturing bonds and finance its budget deficit, according to UBS analysts.
The government has said it has no need to use an EU/IMF safety net that was put in place last month. But Greece also has complained that it is facing "barbaric terms" that will complicate efforts to slash spending and improve competitiveness.
With interest rates on Greek two-year notes soaring above 7% this week from 3% at this time a year ago, the government clearly isn't in a position to raise those funds on its own.
"We think an intervention over the week end is a distinct possibility," UBS economist Stephane Deo wrote in a note to clients Friday.
Randolph of IHS Global said he expects European and IMF officials to take steps to reassure the market about Greece. But he is now less optimistic about Greece's prospects for avoiding default than he was at the start of the year.
That's because it now appears that Germany, Europe's biggest economy and one of the main drivers of the European integration effort that led to the creation of the euro, has grown more self-interested since the current chancellor, Angela Merkel, took office in 2005.
Public opinion in Germany runs against a Greek bailout, in part because the Maastricht treaty governing euro zone relations forbids fiscal transfers between governments. Thus powerful voices in Germany, such as central bank chief Axel Weber, have been heard criticizing EU support proposals.
"Germany under Merkel is no longer willing to pick up the bill," said Randolph. "Since they got the European unification they were looking for, their impulse to help the rest of Europe has grown weaker."