Delinquency rates on mortgages extended to Spanish property developers and construction companies are forecast to rise by a factor of 15 by the end of next year, which could threaten some local savings banks that have experienced above-average growth in lending to these sectors, according to rating agency Moody's.

The Spanish banks have rapidly increased their exposures to real estate over the past decade, fuelled by property price appreciation, which is second only to Ireland in Europe.