# Business diversity by postcode

> How broad each district's registered SIC mix is—and how much one shared postcode dominates it.

- Category: Money
- Cadence: monthly
- Status: Published on a monthly cadence.
- Dataset key: `business-diversity-by-postcode`
- Source: [Companies House](https://download.companieshouse.gov.uk/en_output.html)
- Licence: Open Government Licence v3.0 — [terms](https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/)
- Canonical page: [https://londongraph.com/g/business-diversity-by-postcode](https://londongraph.com/g/business-diversity-by-postcode)
- Machine-readable record: [https://londongraph.com/data/business-diversity-by-postcode](https://londongraph.com/data/business-diversity-by-postcode)

## Methodology

Live companies from the monthly Companies House bulk snapshot, restricted by full postcode to London and aggregated to postcode district. The effective-number measure is the exponential Shannon diversity of declared SIC sections: it rises when registrations are spread evenly across more sections. The shared-address diagnostic reports the share registered at the busiest full postcode; it suggests address concentration but does not identify a formation agent. These are registered offices, not workplaces, jobs or high-street premises. Cells are centroid-based comparison areas rather than Royal Mail boundaries.

## Visualisations

- [Diversity map](https://londongraph.com/g/business-diversity-by-postcode): Select effective SIC diversity, largest-section share or shared-address concentration.
- [Diversity distribution](https://londongraph.com/g/business-diversity-by-postcode?view=distribution): Place effective SIC-section diversity around the mapped London median and quartiles.
- [Scale vs diversity](https://londongraph.com/g/business-diversity-by-postcode?view=scale-vs-diversity): Compare live-company count with the evenness and breadth of the SIC-section mix.
- [District detail](https://londongraph.com/g/business-diversity-by-postcode?view=district-detail): Inspect company count, SIC concentration, unique postcodes and the busiest-address diagnostic.

## Citation guidance

Attribute the original publisher named above and identify LondonGraph as the visualisation and methodology layer. Do not describe live values as a historical census, and do not present placeholder values as observations.