The spread on the German bunds, an eurozone benchmark, narrowed to just 63 basis points, show data by the electronic exchange MTS.

All eurozone sovereign bonds saw yields drop today after the European Central Bank (ECB) announced central banks will start sovereign bond purchases on Monday.

Slovenian yields long tracked Portugal's. In recent days they dropped towards Italy's and Spain's, but now they are well below those as well.

Less than two years ago, at the peak of speculations that Slovenia may need an EU bailout, the yield was above 7%.

After Slovenia bailed out its banks in late-2013, the yield started gradually dropping.

The latest spurt has been helped by the ECB's quantitative easing measures as well as Slovenia's robust GDP growth.