Standard & Poor's raised Spain's credit rating by one notch to 'BBB+' on Friday, citing government economic reforms that have boosted the economy, a day after Prime Minister Mariano Rajoy announced the next general election will be held on December 20.

"Spain's economy has benefited from two rounds of labour market reforms since 2010, which have improved competitiveness of the export and services sector, and from easier financial conditions," it said in a statement.