The transaction, which will be sold under RegS/144A regulations, is expected to price later on Wednesday via bookrunners Barclays, Citi, Santander and Societe Generale.

The dollar market will enable Spain to diversify its investor base and tap into the largest community of yield-hungry emerging markets funds.

Spain has made significant inroads into its hefty EUR120bn funding programme for 2013, raising EUR22bn via a syndicated 10-year bond and a handful of auctions.