---
title: "Mr John Martin Costello — Ownership Dossier"
canonical: https://whiteintel.dev/entity/bd618348-6403-4d3d-9c94-33b08053bd94
json: https://whiteintel.dev/api/public/dossier/bd618348-6403-4d3d-9c94-33b08053bd94
identifier: psc:wn0hvK9icT6ryNf0CSIQBkK8v4o
jurisdiction: GB
risk: Low
source: WhiteIntel corporate-ownership graph
---

# Mr John Martin Costello

**Type:** Person  
**Jurisdiction:** [GB](https://whiteintel.dev/jurisdictions/gb)  
**Identifier:** `psc:wn0hvK9icT6ryNf0CSIQBkK8v4o`  
**Risk level:** Low  
**Canonical dossier:** https://whiteintel.dev/entity/bd618348-6403-4d3d-9c94-33b08053bd94  
**Structured JSON / MCP:** https://whiteintel.dev/api/public/dossier/bd618348-6403-4d3d-9c94-33b08053bd94  

## Ownership & control

### Holdings / subsidiaries

- **CALLANDER DEVELOPMENTS LIMITED** (beneficial owner) — 87.5% — https://whiteintel.dev/entity/ff447d35-c548-57d0-880c-641f87e417d2

## Get the full, resolved dossier (agent-callable)

The above is the free teaser. The resolved **multi-hop UBO chain**, ownership **%**, full **financial history**, itemised **assets** and the hop-by-hop **exposure path** are the paid depth — callable as tools from your agent:

```bash
npx -y @whiteintel/mcp-server   # then: get_dossier · trace_ownership_path · check_offshore_exposure
```

Or unlock a one-off cited dossier for **Mr John Martin Costello** — https://whiteintel.dev/entity/bd618348-6403-4d3d-9c94-33b08053bd94 · pricing https://whiteintel.dev/pricing.

---

_This is the markdown-for-agents view of the WhiteIntel dossier for **Mr John Martin Costello**. Human view: https://whiteintel.dev/entity/bd618348-6403-4d3d-9c94-33b08053bd94 · Structured JSON: https://whiteintel.dev/api/public/dossier/bd618348-6403-4d3d-9c94-33b08053bd94._

_Risk levels are heuristic investigative leads, not legal determinations of beneficial ownership. Every claim carries a source; an absent edge means "not yet observed in current sources", not "does not exist"._