MINUSTAX S.L. is a Spanish software-as-a-service (SaaS) company that offers a platform to help individuals automate their annual income tax returns ("Declaración de la Renta"). The service specifically targets the complexities of reporting capital gains from investments in stocks, ETFs, and cryptocurrencies. By integrating with numerous national and international brokers and exchanges, the platform automatically imports transaction data, calculates tax liabilities, and generates the necessary figures for official tax submission, aiming to make the process fast, accurate, and affordable for retail investors.