Spain\'s borrowing costs surged Thursday as it auctioned 3.75 billion euros ($5 billion) in bonds in the midst of the eurozone debt crisis. The Treasury managed to raise the full amount targetted but had to offer yields of more than five percent to lure interest in the auction of three-, four- and five-year government bonds, the Bank of Spain said. Investor appetite for the bonds had been stimulated by the decision of the world\'s top central banks on Wednesday to pump liquidity into the financial system, said an analyst at Bankinter. Demand for the bonds amounted to 10.255 billion euros, outstripping supply by almost three to one. A breakdown of the bond auction showed: The sale of 1.2 billion euros in three-year bonds was settled with average yields of 5.187 percent, up from 3.639 percent at the previous comparable auction October 6. The sale of 1.4 billion euros in four-year bonds yielded an average of 5.276 percent, up from 4.045 percent at the previous comparable auction February 3. The sale of 1.15 billion euros in five-year bonds yielded 5.544 percent, up from 4.782 percent on October 20. Wednesday\'s action by the European Central Bank, the US Federal Reserve and central banks in Japan, Britain, Canada and Switzerland lowered the Spanish debt risk premium. The extra interest rate demanded for Spanish 10-year government debt when compared to safe-haven German debt fell below 4.0 percentage points after the banks\' intervention. Yields offered in the auction were lower than those available on the open market just before the result was announced.