Information about statutes of the company, turnover, board of management, shareholders, whether the company is still active or not, available through various online companies, but practically all will ask for a fee and you need to register to make use of their services.
If you know where the company is located and you are in a position to travel there, you can also try to visit the Mercantile Register locally, or in the province´s capital.
LINK to an example of a report, click ´ver ejemplo´ (no personal experience, use of website at member´s discretion).
the Registradores website is an official one, we also refer members to their online office to check on property registrations. They get their information directly from the Mercantile Registers in Spain.
You can of course also engage the services of a gestor to obtain the information you need for you, especially if you´re not fluent in Spanish.