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Infrastructure analysis

Who the published FTSE 100 and S&P 500 constituents rely on for hosting, mail, DNS and domain registration — aggregated from the same passively-collected facts each company page shows individually. Each square below is one company; hover it for the name. Provider names beyond a plain hostname match are best-effort classification, not a vendor's own claim — see how providers are identified.

Not every collector reaches every company, so these charts do not all share one denominator — each states its own. Coverage & method sets out what has actually been collected, for which index, and what has deliberately not been.

Hosting / ASN

132 of 177 companies have an identified hosting provider, sampled from each company's own primary site. 11 more providers used by a single company each, not charted. For the fuller picture — every subdomain of every related domain too — see the full ASN map.

Mail providers

170 of 177 companies have identified MX records. 47 more providers used by a single company each, not charted.

DNS / nameserver providers

177 of 177 companies have identified nameservers. 154 more providers used by a single company each, not charted.

Registrars

176 of 177 companies have an identified registrar. 61 more registrars used by a single company each, not charted.

"Self-hosted" means the record points back at the company's own registrable domain rather than a third-party vendor's — not a claim about what actually runs the infrastructure behind it.

Sector

94 of 177 companies classified, from the primary SIC code on their Companies House record — a UK-incorporation-only signal, so a constituent with no Companies House match has no sector here rather than a guessed one.

Security headers

Read from each company's primary site during the same crawl every company page shows individually. "All three" means HSTS, a Content-Security-Policy and X-Frame-Options (or an equivalent CSP frame-ancestors directive) are all present at once — not that the policies themselves are strict. 66 of 131 sites set all three; 12 set none.

Domain age

175 of 177 companies have a primary-domain registration date from RDAP/WHOIS. A registration date is when the domain was first registered under its current run — not necessarily when the company itself was founded, since a domain can be re-registered, transferred or renamed. Expiry dates already in the past are excluded from "soonest to expire" rather than shown as overdue.

By decade first registered: 1980s: 12, 1990s: 105, 2000s: 30, 2010s: 21, 2020s: 7.

Notable external links

Domains a company's primary site links to, counted by how many distinct companies link there — filtered to exclude generic social/platform destinations (LinkedIn, YouTube, Google, etc.) so what's left is regulators, share registrars, industry bodies and similar third parties that actually say something about who a company deals with. 13125 distinct external domains were linked to in total; the table below is the notable subset only.

See how the same infrastructure picture compares against 250 more companies just outside the index in the FTSE 100 vs FTSE 250 baseline.