The financial crisis led to detailed scrutiny of OTC (over-the-counter) derivatives and resulted in a raft of new international regulations designed to make derivatives more transparent. In 2009, the G20 leaders agreed to reforms in the OTC derivatives markets to achieve central clearing and, where appropriate, exchange or electronic trading of standardized OTC derivatives, along with reporting of all transactions to trade repositories and higher capital as well as margin requirements for non-centrally cleared transactions. Within the European Union, these objectives have been implemented through the European Market Infrastructure Regulation (EMIR). EMIR entered into force on 16 August 2012. Reforms in the U.S. were being carried out under the Dodd-Frank Wall Street Reforms and Consumer Protection Act (Dodd-Frank Act) and on July 21, 2010, the Dodd-Frank Act was signed into law by President Obama.Regulatory reforms have already had an impact on OTC derivatives market structures and volumes. In this paper we take a brief look at the current state of the OTC derivatives market reforms and analyse their potential impact. In particular, we focus on the trends in market volumes (notional amounts of outstanding OTC derivatives contracts, OTC derivatives by contract type, gross market values of OTC derivatives) before and after regulatory reforms were introduced.