The authors would like to thank Rowena Crawford for assistance with the analysis, and Alex Beer, Carl Emmerson and David Sturrock for helpful feedback and comments. The authors would also like to thank Laurence O'Brien for assistance with the Annual Survey of Hours and Earnings (ASHE) data. This report is an output from a programme of research on 'Pension Saving over the Lifecycle' that is funded by the Nuffield Foundation under grant WEL /FR-000000374. Co-funding from the ESRC-funded Centre for the Microeconomic Analysis of Public Policy (ES/T014334/1) is also gratefully acknowledged. This work was produced using statistical data from the ASHE, provided by the Office for National Statistics (ONS). The use of the ONS statistical data in this work does not imply the endorsement of the ONS in relation to the interpretation or analysis of the statistical data. This work contains statistical data from HM Revenue and Customs (HMRC) which is Crown Copyright. The research data sets used may not exactly reproduce HMRC aggregates. The use of HMRC statistical data in this work does not imply the endorsement of HMRC in relation to the interpretation or analysis of the information.The Nuffield Foundation is an independent charitable trust with a mission to advance social well-being. It funds research that informs social policy, primarily in Education, Welfare, and Justice. It also funds student programmes that provide opportunities for young people to develop skills in quantitative and scientific methods. The Nuffield Foundation is the founder and cofunder of the Nuffield Council on Bioethics, the Ada Lovelace Institute and the Nuffield Family Justice Observatory. The Foundation has funded this project, but the views expressed are those of the authors and not necessarily the Foundation. Visit www.nuffieldfoundation.org.Understanding pension saving among the self-employed