Spain's borrowing costs leapt in a major bond market test Thursday as Madrid prepared to unveil the price of a banking rescue that has stoked fears of a full-blown bailout.
Spain showed it can still tap the market at a pivotal time, with a eurozone rescue loan of up to 100 billion euros ($125 billion) in the works and fears mounting that a state bailout could follow.
The Treasury raised 2.22 billion euros, beating its own target, and demand outstripped supply by more than three times for the mixture of two-, three and five-year bonds, Bank of Spain figures showed.
But it had to pay soaring rates to lure investors.
The yield more than doubled to 4.706 percent from 2.069 percent at the last comparable sale March 1 for two-year bonds, a sign of deep misgiving about Spain's near-term prospects.
The rate on three-year bonds climbed to 5.457 percent from 4.876 percent on May 17, while for five-year bonds it leapt to 6.072 percent from 4.960 percent on May 3.
Spain's eurozone partners agreed on June 9 to lend up to 100 billion euros to save stricken banks that made reckless loans during a real estate bubble that imploded in 2008.
The government says the size of the banking rescue will depend on two audits of the banks whose results are due to announced later Thursday, one from the German firm Roland Berger, the other from the US firm Oliver Wyman.
With those audits in hand, the government is officially to request a banking sector rescue.
In Brussels, a source said Spain would lodge the request at a eurozone meeting in Luxembourg later in the day. Another eurozone source said the amount would be "well within" the maximum 100 billion euros.
"The market has priced in a grim report of Spain's banking system," said Ishaq Siddiqi, London-based market strategist at brokerage ETX Capital Market.
"Much of the focus will be on how Spain will use the bailout funds for its banks -- or worse, if it needs more funding than anticipated."
Far from calming markets, the banking rescue pushed Spain's borrowing rates to the highest levels since the birth of the euro in 1999 as investors fretted over the impact of the loan on Spain's booming debt.
The banking bailout further undermined confidence because it lacked details such as the price and conditions while highlighting Spain's difficulties in raising money on the markets.
Spain could rapidly need a state bailout, said a report by financial research group Rabobank's fixed income strategists Richard MacGuire and Lyn Graham-Taylor.
Once bond yields exceeded seven percent, Greece and Ireland had only held out for weeks while Portugal, which had not had a banking crisis, lasted almost five months, the analysts said.
The Spanish crisis most resembled Ireland's, with a tight relationship between banks and the state, they said, and the threat was elevated by Spain's credit rating, now hovering just above junk-bond status with Moody's.
"The bottom line, then, is that it seems hard to countenance Spain avoiding a more comprehensive bailout," the Rabobank strategists said.
Spanish yields eased this week after a Group of 20 summit in Los Cabos, Mexico, raised expectations that European authorities could step in by cutting interest rates or possibly purchasing the bonds of Spain and Italy.
Spanish 10-year bond yields, which pierced a euro-era record above seven percent Monday, traded at 6.6 percent late Thursday morning, a rate still viewed as unsustainable over the long term.
Spain's battle to rein in its mushrooming sovereign debt, especially during a recession with unemployment at 24.4 percent in the first quarter, is the major concern of investors.
Even the International Monetary Fund has said Spain will likely fail to meet targets to trim annual deficits from 8.9 percent of economic output last year to 5.3 percent this year and 3.0 percent in 2013.
If Spain adds a 100-billion-euro banking loan to its books, public debt would expand by about 10 percentage points and could hit 90 percent of economic output by the end of this year, analysts say.
Already, Spanish people are in the streets weekly protesting about the pain inflicted by austerity cuts.
On Wednesday, tens of thousands of public sector workers vented their anger at the banking bailout in demonstrations called in dozens of towns to protest spending cuts.