There are many different transactions that can take place in Capital Markets, including equity or debt securities, commodities, FX or derivatives.
Since large capital is being exchanged here the regulations are very strict. Regulators from all around the world provide regulatory guidance for all the parties involved.
In the EU, MiFID and MAD/MAR regimes are the most notable regulations in respect of Capital Market regulations.
These sets of rules provide clear guidance on required activities and responsibilities among the different actors.