On this page you can follow the value of the Spanish risk premium minute by minute. The value of the premium indicates the risk that financial markets assign to a country's debt. The larger that value, the greater the financing cost that the country must pay and therefore the greater your risk of bankruptcy.
In the case of Spain, the risk premium is calculated based on the German risk premium, so a value of 400 points means that the differential Between the German and the Spanish risk premium it is 400. For example, if it costs Germany 1,3% to finance itself and Spain has a differential of 400 then the cost of financing in Spain is 5,3%. This value is obtained by adding 130 + 400 = 530 (5,3% as a percentage).
The risk premium has become sadly famous in Spain as a result of the sovereign deduct crisis of the year 2011 that raised the value to figures above 500 points. In this situation, a country cannot finance itself in the markets, so the risk of default it's huge.