Regulatory filing for AIM and Main Market companies. ESEF/UKSEF format compliance. Inline XBRL for primary statements. FCA Listing Rule requirements met.
The NSM is the UK's official repository for regulatory documents. Listed companies must submit annual reports, interim reports, and other regulated information to an FCA-approved NSM provider. Think of it as the "public archive" for capital markets—investors, analysts, and regulators access your filings here.
European Single Electronic Format (ESEF) or UK variant (UKSEF). Depends on your listing type and accounting period.
| Format | Applies To | Requirements |
|---|---|---|
| ESEF EU Standard |
Main Market premium listings with accounting periods ending before 31 Dec 2024 (EU Transparency Directive compliance retained during transition). Also applies to: EU-listed companies, dual-listed UK/EU companies filing under EU regulations |
|
| UKSEF UK Standard |
All UK-listed companies with accounting periods ending on or after 1 Jan 2025 (FCA PS24/6 implementation). Includes: Main Market (premium/standard), AIM, Aquis, AQSE. Replaces ESEF for UK-only listings post-Brexit. |
|
We handle both ESEF and UKSEF at the same fixed price. Most UK-listed companies will use UKSEF from 2025 onwards (simpler than ESEF, fewer mandatory tags). If you're dual-listed UK/EU or have EU investors, you may need to file both ESEF (for EU) and UKSEF (for UK)—we prepare single source file and generate both formats (small additional charge: £500-£750 for dual format preparation).
Inline XBRL tagging required for primary financial statements. Notes can be block-tagged (UKSEF) or anchor-tagged (ESEF).
UKSEF: Allows block tagging (entire note tagged as single block, less granular). Saves tagging effort. ESEF: Requires anchor tagging (every figure in notes must be individually tagged to taxonomy concept). More detailed but more time-consuming. We recommend UKSEF for UK-only listed companies (simpler compliance). For Main Market premium or dual-listed, ESEF may be required depending on listing timeline and regulatory obligations.
Choose your NSM provider (or we'll recommend one). We handle electronic submission to your chosen provider.
London Stock Exchange's NSM. Most common for Main Market and AIM companies. Integrated with LSE announcements platform.
Independent NSM provider. Popular with AIM companies seeking lower-cost alternative to RNS. ESEF/UKSEF compliant.
Other FCA-approved NSM providers available. We integrate with any approved provider. Full list on FCA website.
NSM subscription is separate from our iXBRL tagging service. You pay NSM provider directly for annual subscription (typically £800-£3,000 depending on provider and company size). We charge fixed fee for ESEF/UKSEF preparation and electronic submission to your NSM provider (£2,500-£5,000 depending on report complexity). Total cost: Our fee + NSM subscription.
Different deadlines and disclosure rules depending on which market you're listed on.
From ESEF/UKSEF preparation to live NSM publication.
We receive your finalized annual report (PDF or Word). Convert to XHTML format (required for ESEF/UKSEF—not PDF). Apply inline XBRL tagging to primary statements (balance sheet, P&L, cash flow, equity). Tag notes using block tagging (UKSEF) or anchor tagging (ESEF). Create extension taxonomy for entity-specific line items not in standard taxonomy. Typical turnaround: 5-7 business days for ESEF/UKSEF preparation.
Run XHTML validation (W3C standards compliance). Perform XBRL calculation validation (totals match tagged values). Check taxonomy compliance (correct taxonomy version, valid concept usage). Test extension taxonomy (no duplicate concepts, proper anchoring). Run ESMA validator (for ESEF) or FRC validator (for UKSEF). Generate validation report showing pass/fail for each test. Fix any errors flagged.
Client portal shows XHTML preview (rendered in browser exactly as NSM will display). Board reviews and approves for publication. For AIM companies: Nominated Adviser (NOMAD) reviews and approves (AIM Rule requirement—cannot submit without NOMAD sign-off). Digital approval signatures captured for audit trail. Portal shows approved status with timestamp.
Upload XHTML package to NSM provider portal (RNS, Morningstar, etc.). Provide metadata: company name, ticker symbol, report type (annual report), period covered, publication date/time. NSM provider performs instant validation (XHTML integrity, XBRL schema check). Returns acceptance or rejection within 1-2 minutes. If accepted, NSM reference number issued (e.g., "NS202412110001").
NSM provider queues document for publication (typically 2-4 hours after submission). XHTML file becomes searchable on NSM provider's public website (e.g., londonstockexchange.com for RNS). Investors, analysts, and regulators can access immediately. FCA receives automatic notification (NSM provider notifies FCA of all submissions). Document permanently archived (7+ year retention as per FCA rules).
While NSM publication happens, we also file with HMRC (CT600 + iXBRL accounts) and Companies House (iXBRL accounts). Three parallel submissions using same underlying accounts data. Different format requirements: HMRC accepts FRC taxonomy iXBRL (UK GAAP), Companies House accepts same file, NSM requires ESEF/UKSEF XHTML. We prepare both formats from single source—no duplicate work for client.
Portal updated with NSM publication confirmation (link to live NSM document, publication timestamp, NSM reference number). Email sent to board/company secretary with submission receipts (HMRC, Companies House, NSM). All documents archived in client portal for 7 years. Submission certificates provided (proof of on-time filing for FCA compliance records). Next year deadline calculated and calendar reminder set.
For Main Market: FCA may initiate enforcement investigation (serious regulatory issue). Trading suspension possible if persistent non-compliance. Reputational damage with investors and analysts. For AIM: LSE issues formal censure. NOMAD required to explain failure to FCA. Potential suspension from AIM if repeated failures. Unlike Companies House (automatic penalty), FCA action is discretionary but can be severe. We recommend filing 2-3 weeks before deadline to allow buffer for any last-minute issues. Our guarantee: If we cause delay, we cover any FCA penalties up to £5,000.
Currently: Only annual reports require ESEF/UKSEF format (FCA DTR 4.1). Interim reports (half-yearly, quarterly) can be filed as PDF to NSM (no XBRL tagging required). Future: FCA consultation (PS24/6) proposes extending UKSEF to interim reports from 2027 onwards (not yet finalized). Recommendation: File interim reports as PDF for now. Monitor FCA announcements for timeline on interim UKSEF requirement. We'll notify clients when regulations change.
Technically yes—you can prepare ESEF/UKSEF XHTML and submit directly to NSM provider if you have in-house expertise. Reality: ESEF/UKSEF preparation requires specialized XBRL software (£5,000-£20,000/year licenses like Workiva, Certent, Toppan Merrill) and trained staff (XBRL taxonomy knowledge, XHTML coding skills, regulatory compliance awareness). Most companies outsource to specialists like us. DIY risk: XBRL errors cause NSM rejection → rush to fix → potential deadline miss → FCA enforcement. Our service includes: XBRL software licenses (you don't buy), expert tagging team, validation tools, NSM submission management, resubmission guarantee. Total cost lower than in-house (unless you're very large company filing 100+ entities annually).
Typical all-in cost breakdown: (1) Our ESEF/UKSEF preparation + NSM submission fee: £2,500-£5,000 (depends on report complexity—simple AIM company vs complex Main Market group). (2) NSM provider annual subscription: £800-£3,000 (paid direct to RNS/Morningstar/etc.). (3) HMRC + Companies House filing: Included in our fee (simultaneous filing at no extra charge). (4) Extension taxonomy creation (if needed): £500-£1,500 extra (if you have entity-specific line items not in standard taxonomy). (5) NOMAD review fee (AIM only): £1,000-£5,000 (paid direct to your Nominated Adviser—separate from our fee). Total typical cost: £4,800-£14,500 annually for AIM company with NOMAD. £3,800-£8,500 for Main Market (no NOMAD). Much cheaper than in-house team (£50k-£100k salary + software licenses + training).
ESEF/UKSEF preparation. NSM submission. HMRC + Companies House filing. All included. Next: Post-filing support.
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