Seems they think there are foreign buyers eager to take advantage of the new residency laws..
http://www.telegraph.co.uk/expat/before-you-go/10063966/Residency-law-gives-the-Spanish-market-a-boost.html
Spanish property is set to become particularly attractive this summer, as a new law expected to come into force by July will allow non-EU residents to get Spanish residency automatically if they buy a property worth €500,000 or more.
Foreign investment in the Spanish property market has increased by 17pc in 2012, according to the latest figures from the Bank of Spain, taking it to a level not seen since 2004. The market has become increasingly attractive as a result of the significant falls seen in property prices since it was enveloped in the financial crisis.
Back in 2003, around €7 billion was invested during the Spanish property boom, but in 2009, just over half of this amount was invested, at €3.6 billion. Since then, however, the figures have improved, with €5.54 billion being spent last year.