National Savings and Investments (NS&I), formerly called the Post Office Savings Bank and National Savings, is a state-owned savings bank in the United Kingdom. It is both a non-ministerial government department and an executive agency of HM Treasury. The aim of NS&I has been to attract funds from individual savers in the UK for the purpose of funding the government's deficit. NS&I attracts savers through offering savings products with tax-free elements on some products, and a 100% guarantee from HM Treasury on all deposits. As of 2017, approximately 9% of the government's debt is met by funds raised through NS&I, around half of which is from the Premium Bond offering.

His Majesty's Treasury, occasionally referred to as the Exchequer, or more informally the Treasury, is a ministerial department of the Government of the United Kingdom. It is responsible for developing and executing the government's public finance policy and economic policy. The Treasury maintains the Online System for Central Accounting and Reporting, the replacement for the Combined Online Information System, which itemises departmental spending under thousands of category headings, and from which the Whole of Government Accounts annual financial statements are produced.