DRAFT v0.1 / FILE REF CDD/2026/UK-MID-MKT / INDEPENDENT REFERENCE - NOT M&A ADVICE
§ CHAPTER I
I.

Market Sizing Due Diligence

Chapter I of the seven-chapter CDD spine.

§ DIRECT ANSWER

Chapter I of the CDD spine: Market Sizing Due Diligence. The chapter answers the IC’s primary question for this leg of diligence and cites the primary UK sources it draws on. Source: ICAEW Corporate Finance Faculty; BVCA Industry Activity.

Chapter I sizes the addressable market top-down (industry reports, ONS, trade body data) and bottom-up (customer count x ARPU). Triangulation across the two is the only defensible IC slide. Top-down alone is reverse-engineered consultant slop; bottom-up alone is single-source risk.

§ 1.1Primary UK sources

§ 1.2Worked example

See /worked-examples/market-sizing-bolt-on/ for a £60m UK bolt-on triangulation.

§ 1.3IC challenge

The IC will challenge any TAM that flatters the synergy case. Match the chapter footnote to the IC-summary slide footnote; do not let them diverge.

VERIFIED 21 JUN 2026NEXT REVIEW 21 SEP 2026SRC: ICAEW CF; BVCA Industry Activity 2025-26

Marked-up by Oliver Wakefield-Smith. Draft v0.1, 21 June 2026.