Feb. 13 (Bloomberg) -- Banco Santander SA and Banco Bilbao Vizcaya Argentaria SA were among 15 Spain-based financial firms downgraded by Standard & Poor’s, after the credit-ratings company reduced the nation’s grade last month.

Santander, Spain’s biggest bank, was lowered to A+ from AA-, while BBVA was reduced to A from A+, S&P said today in a statement. Both have a negative outlook, S&P said. The ratings company had cut the grade on Spain’s long-term debt to A from AA- on Jan. 13.

To contact the reporter on this story: Patrick Clark in New York at pclark48@bloomberg.net

To contact the editor responsible for this story: David Scheer at dscheer@bloomberg.net