Spain's borrowing costs leapt in a major bond market test Thursday as Madrid prepared to reveal audits showing how much money its banks need from a vast eurozone rescue loan.
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 the results of two audits due in the afternoon, one from the German firm Roland Berger, the other from the US firm Oliver Wyman.
A second, more detailed study to be carried out by Deloitte, KPMG, PwC and Ernst & Young, is to look at the valuation of banking assets, and is due July 31.
"The markets expect that the results will find a capital shortfall of 60-70 billion euros," said Kathleen Brooks, research director for brokerage Forex.com.
"Anything larger than 100 billion euros may cause another bout of market panic, causing Spanish and Italian bond yields to surge and risk assets to tumble," she warned.
The government was to request a banking sector rescue "in the coming days," Finance Minister Luis De Guindos said on arrival for eurozone ministerial talks in Luxembourg.
De Guindos said he would explain the banking woes to his colleagues, describing the formal request as a "mere formality".
Far from calming markets, the banking rescue sent 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.
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 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 eurozone authorities could cut interest rates or even purchase Spanish and Italian bonds.
Spanish 10-year bond yields, which pierced a euro-era record above seven percent Monday, traded at 6.57 percent in the late afternoon, a rate still viewed as unsustainable over the long term.
The gap between Spanish and safe-haven German bonds -- known as the risk premium -- narrowed at one point to 4.91 percentage points before pushing back to 5.05 percentage points.
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.
Spanish debt stood at 36 percent of economic output before the country's property bubble burst.