How we built this dataset
There is no single global bunker market. BunkerStrategy separates transferable bunker real estate from embedded shelter, products, and broader-property contexts — so a country median, a $/m² figure, and a listing badge all carry the same mental model.
Certified comparable rows require a public price, normalizable currency, stated underground area, a defensible source URL, and a clear scope statement. Everything below is a guardrail on top of those four ingredients — not a workaround for them.
Guardrails before any country median
Read country medians inside the right market lane, not across them. Taipei micro-title parking shelters, Singaporean apartment Mamads, Swedish ex-defence mountain halls, and Atlas-E silos are different products with different denominators.
- Lane disciplineEvery listing is badged with its market lane (transferable RE, embedded shelter, product, lifestyle, micro-title parking, adaptive reuse, source-limited, or unknown). Medians and comparisons must stay within a lane.
- Tiny denominators are flagged, not averagedWhen a row has under 50 m² of stated underground area — ROC posts, parking-cum-shelter units, cellar shelters — $/m² is suppressed in favour of the absolute price, because the denominator dominates the figure.
- Broader-property prices stay visible but don't enter mediansApartment, villa, and townhouse rows that bundle a shelter or basement keep their evidence role, but their headline price is broader-property pricing — not shelter pricing.
- No global bunker medianThe dataset does not publish a single global bunker $/m² median, because no such number is meaningful. Counts and distributions are global; medians are always lane- and country-scoped.
What we track
BunkerStrategy maintains a global research dataset of bunker, civil-defense shelter, missile silo, hardened underground residence, and command-facility listings. Each row is a real-world property: either a current asking price, a recorded sale, an auction result, or a piece of supporting evidence for a market that has very little public liquidity.
We focus on assets that a private buyer could plausibly acquire and operate — not generic construction services, memberships, or marketing brochures.
Where the data comes from
Every priced row is anchored to at least one public source. The dataset draws from:
- Real-estate marketplaces — Hemnet, Boliga, Rightmove, Funda, SS.com, Domain, regional MLS aggregators.
- Specialty broker pages — operators that catalogue ex-military, missile-base, and earth-sheltered properties.
- Government disposal portals — defence-property sales, civil-defence shelter releases, and municipal auction archives.
- News and trade press — when an article preserves the asking price, sale price, or auction result with the underground area.
Each row stores its source URL and the date it was retrieved, so any number on the site can be traced back to public evidence.
How we normalize prices
Listings come in dozens of currencies and area units. Every price is normalized to a common currency at a static reference rate, then divided by the underground area in square metres to produce a single comparable unit: USD per underground m². That figure is what powers every median, ranking, and value score on the site.
Square-foot disclosures (mostly North American) convert at 0.092903 m² per ft². Total asking prices and medians are also displayed in USD.
A row is only used in country medians if the source states both the price and the underground area. Rows where one is missing stay visible as evidence but never enter a median.
How we score quality
The quality score reflects what is physically inside the property — not its location or marketing. It rewards concrete hardening attributes:
- Hardened structure, blast doors, and reinforced entries
- Independent power, water, and ventilation/filtration systems
- Underground area, condition, and required renovation burden
- Buyer accessibility — whether the asset is realistically transferable
Synthetic demo rows and low-confidence sources are capped so they cannot rank above thoroughly documented properties.
How is the Best Transferable Market chosen?
The Best Transferable Market badge picks a country whose bunker real-estate evidence is both well-priced relative to comparable properties and backed by enough trustworthy listings that the result isn't a fluke.
Cheapness alone isn't enough. A country can show a low median because it only has one or two thinly-documented rows — that's a cohort the badge will skip, not celebrate. To be considered, a country must have at least three transferable bunker real-estate listings that already passed the same gates the rest of the dashboard uses (real source, stated price, stated underground area, recognisable real-estate scope).
For each qualifying country, the badge looks at every transferable row and combines three pieces of evidence per row: how the price compares to similar properties, how richly the listing is documented, and how confident the pipeline is in the underlying source. The country whose rows score best on average wins.
In short: the badge rewards markets where the listings are genuinely cheap and the evidence holds up — not the country with the single lowest number.
How we score value
The relative value score compares a property's price-per-m² against the median of its asset-type cohort and its country cohort. A small, well-hardened bunker priced well below comparable bunkers scores high; the same asset priced above comparable houses scores low. Confidence in the source and any required renovation work moderate the result.
Markets get their own roll-up signal — high, medium, low, thin, insufficient, or not comparable — derived only from priced rows that meet the comparable standard.
What "certified comparable" means
A row earns the certified label when the public source clearly states all four ingredients of a real comp:
- A defensible URL that still resolves (live, archived, or a verifiable replacement)
- A specific asking, sale, or auction price for the asset
- An asset-specific underground area — not a whole-house figure that happens to include a shelter
- A scope statement: whether the price covers the whole property, just the underground component, or a leasehold right
Rows that fall short — price-on-request pages, broader-property prices, brochure-only evidence, or shelters that may not be separately transferable — are kept visible for context but do not enter country medians.
Status badges, in plain English
- Active — the property is currently advertised for sale.
- Disposal — listed on a government or municipal disposal portal.
- Broker — held on a specialty broker's catalogue page.
- Sold / Archived — recorded sale or expired listing, retained as historical evidence.
- News / Evidence — supporting article or secondary record, not a primary listing.
- Demo — synthetic example row, never used in country medians.
Coverage gaps and caveats
- Public visibility varies wildly. Western Europe and North America have deep listing portals; many emerging markets and conflict-adjacent regions don't. Coverage gaps are explicit, not silent.
- Asking vs. sale. Most rows are asking prices. Where a sale or auction result is available, the row records the actual transaction price.
- Historical prices are not inflation-adjusted. Older auction results read as market-depth evidence, not current pricing.
- Active supply is small. The market is illiquid by nature — a single high-spec bunker can be the only one for sale in a country in a given quarter.
- Data is research, not investment advice. Nothing on this site is a recommendation to buy, sell, or value a specific asset.