Most of this report is descriptive and analytical, explaining why and how central banks oversee payment and settlement systems. It looks at the need for oversight, the source of central banks’ responsibilities for oversight, the scope of oversight and the activities that oversight involves. In addition it looks at cooperative oversight, where more than one central bank or other authority has responsibilities for a system. However, as well as this description and analysis, the report also includes 10 principles for effective oversight, each with explanatory text. Five of the principles are generally applicable to oversight arrangements while the other five are specifically for cooperative oversight arrangements. All the principles are consistent with, and indeed largely drawn from, the previous work on payment and settlement systems published by the Committee and earlier groups reporting to the G10 Governors.