This is what happens when people quit buying Treasury Bonds of a country.
Spain has become the latest point of concern in Europe’s debt crisis as investors are concerned over the ability of the government to push through its big austerity program at a time when its economy is heading for a return to recession and unemployment is standing at around 23 percent. The yield on the country’s 10-year bond pushed up to 5.74 percent, a sign that investors are wary of Spain’s ability to avoid suffering the same bailout fate as Greece, Ireland and Portugal.

The eurozone crisis remains unresolved and Spain remains in the spotlight with bond yields moving higher after yesterday’s disappointing bond auction.

Spain sold 2.6 billion euros of 2015, 2016 and 2020 bonds - at the low end of its target range - and the average yield rose on all three.

"It was only a lukewarm auction," DZ Bank rate strategist Michael Leister said. "The key thing here is the volume, they fell well short of the maximum range they intended to sell."

"This shows that the LTRO (ECB's long-term refinancing operation) effect is losing momentum and that Spain is having a much more difficult time."

The ECB injection of 1 trillion euros in cheap 3-year funds has helped depress borrowing costs for struggling euro zone governments since December, easing concern over the debt crisis.

But with no further injections on the cards and in the face of problems with high debt and chronically low growth, yields on Italian and Spanish government debt have crept higher.