This publication considers the investment choices of insurance companies, self-administered pension funds, investment trusts, unit trusts and property unit trusts. Before viewing this MQ5 publication, it is recommended that readers familiarise themselves with the institutional groups covered within. These institutions control £4 trillion of assets and engage in considerable volumes of investment activity to fund their operations. An understanding of their investments and assets is important to monitor the stability of the financial sector and is used in the compilation of the UK National Accounts. The MQ5 release includes quarterly net investment data arising from financial transactions (investments) made by these institutions. Also included are quarterly balance sheet data for short-term assets and liabilities, plus quarterly income and expenditure data for insurance companies and self-administered pension funds. All data are reported at current prices (effects of price changes included). The Office for National Statistics (ONS) makes every effort to provide informative commentary on the data in this release. As part of the quality assurance process, individual businesses are contacted to capture reasons for extreme period-on-period data movements. It can prove difficult to elicit detailed reasons from some businesses to help inform the commentary. Frequently, reasons given for data movements refer to a “change in investment strategy” or a “fund manager’s decision”. Consequently, it is not possible for all data movements to be fully explained. This release contains final estimates for 2017, based on these institutions’ balance sheets at the end of 2017, the latest period for which annual results incorporating balance sheet information are available. Due to the discontinuation of the MQ5 publication, there will be no opportunity to incorporate annual survey data for 2018. This quality assurance process is used to align quarterly survey data with annual survey data and can lead to significant revisions, but the 2018 estimates in this final MQ5 publication will not be subject to annual alignment. Similarly, there will be no further revisions to 2018 data following this publication, due to respondent revisions. Therefore, the 2018 estimates should be regarded with due caution. It is sometimes necessary to suppress figures for certain items to avoid disclosing investment activity by individual institutions. In these cases, the figures are usually combined with those for another item, and this will be indicated in the tables with a footnote. All estimates are reported on a current price basis (that is, they are not adjusted to remove the effects of inflation). A Glossary is available to assist your understanding of the terms used in this release. Please note, temporal coverage of individual MQ5 components vary.