The European Central Bank has pulled out all the stops over the past few months to prevent a credit crunch by providing banks with €1 trillion in ultra-low cost financing.

That €1 trillion move, which was hailed as a game changer, helped ease pressure on eurozone nations as some banks used the money to buy government bonds.

But the potency of the ECB's two long-term refinancing operations, or LTROs, appears to be fading as yields on Spanish and Italian bonds have shot higher in recent weeks.