The Official Gazette publishes the Ministry’s Order approving the Form 231 for Country by Country Reporting.
This tax form must be filed by Spanish-resident ultimate parent company or designated entities for groups with a consolidated turnover amounting to at least 750 million euros. The filing period starts at the year-end of the parent company and lasts for 12 months.
Spanish-resident subsidiaries are also required to file Form 231 when the ultimate parent company or the designated entity reside in a tax jurisdiction not having CbC reporting obligations, nor an automatic tax information exchange agreement with Spain, nor effective information exchange with the Spanish Tax Authorities.
More information: Official Gazette (in Spanish)
Separately, any Spanish resident company or permanent establishment must report to the Spanish Tax Authorities about the name and tax jurisdiction of the ultimate parent company and designated entity to file CbC reporting by year-end (for most companies the deadline is 31 December). An electronic reqest form has been enabled in the tax authorities website for these purposes.