Green Book — October 2026 appraisal update
What it examines
Updates social discounting guidance, with a headline real rate of 3.00% for the first 30 years and separate treatment signposted for overseas aid. New guidance also describes voluntary business cases for packages of investment in a place. Individual project appraisal and each partner’s spending approvals remain necessary.
Why it matters
Relevant to how UK public investment is appraised and coordinated. Social discount rates value future public costs and benefits; they are not commercial return targets for financial institutions. A place business case does not itself approve the spending it describes.
The date refers to the October 2026 appraisal update and accompanying guidance, rather than the original publication of the Green Book.
Institutions and themes
Related documents
Catalogue entry reviewed 29 Oct 2026. The summary describes the publication’s analysis; it does not establish that historical findings remain current.