There is a lot of noise in the debate about the deal, much of it relating to how to place a value on future obligations.
One element in this is how to think about the value at maturity of the new long-term bonds. 25 billion euro of bonds will be placed at the central bank.
The interest costs of these bonds will vary with the euribor (plus a fixed spread).
However, the nominal value of the principal is fixed.
2013 GDP is about 168 billion euro, so 25 billion is 15 percent of 2013 GDP.
The average maturity of the bonds is 34/35 years.
If nominal GDP growth is 2% a year for the next 35 years (0% real + 2% inflation for example), 2048 GDP will be 336 billion, so the maturity value of the debt will be 7.4 percent of GDP.
If nominal GDP growth is 3% a year, 2048 GDP will be 473 billion, so the maturity value of the debt will be 5.3 percent of GDP.
If nominal GDP growth is 4% a year, 2048 GDP will be 663 billion, so the maturity value of the debt will be 3.8 percent of GDP.