The Markets in Financial Instruments Directive I (MiFID I) is a European Union regulation that was implemented in 2007 to enhance transparency and investor protection in financial markets. It aimed to create a single market for investment services and activities across EU member states, ensuring that firms operate under consistent rules. MiFID I established a framework for the regulation of financial instruments, including stocks, bonds, and derivatives. It required firms to provide clear information to clients, conduct best execution practices, and adhere to strict reporting obligations, thereby promoting fair competition and improving market efficiency.