This morning's bond auction will see Spain attempt to raise up to €2.5bn by selling two types of bond – one matures in 2014, and the other in 2022.
The 10-year bonds will be most closely watched as long-term debt is seen as a better measure of market confidence.
Analysts will look at four factors when evaluating the auction: how much debt was sold; how oversubscribed the auction was (bid-to-cover ratio); what interest rate (the yield) Spain has agreed to pay; and whether investors favoured the 2014 bond over the 2022 one.
On Tuesday, Spain held an auction of short-term bonds. Yields jumped, but the auction was still seen as a success because the Spanish authorities actually sold more than their maximum target of €3bn.