Decree-Law No. 233/2004 is a legal framework in Portugal that establishes the regime of transparency for public companies and their subsidiaries. It aims to ensure the transparency and accuracy of information that is provided to the market and investors by these companies. The law sets out requirements for financial reporting, disclosure of information, and communication with shareholders. It also provides guidelines for insider trading, related party transactions, and corporate governance. This law was an important step in promoting transparency and accountability in the Portuguese market, and it helped to align Portugal's legal framework with international standards.