All UK limited companies, LLPs above audit thresholds, charitable companies, and listed companies must file in iXBRL format. Comprehensive coverage of entity types, size thresholds, and exemptions under current HMRC and Companies House regulations.
All UK limited companies must file in iXBRL format regardless of size or activity. The UK has no exemptions with universal iXBRL requirements.
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The UK's iXBRL requirements apply to different entity types with specific thresholds, exemptions, and timelines. Understanding your entity classification is essential for compliance.
All UK limited companies incorporated under the Companies Act 2006 must file their statutory accounts and Corporation Tax returns in iXBRL format, regardless of size, turnover, or activity status.
Unlike many jurisdictions, the UK has no exemptions for limited companies based on size, dormancy, or activity.
Micro-entities: Simplified accounts. Small companies: Abridged accounts option. Medium and large companies: Full accounts mandatory. Quoted companies: Complete strategic and directors' reports required.
CT600 form with full computations. Mandatory iXBRL tagging of accounts and computations. No paper filing accepted since 2011. All company sizes must comply.
Companies House: 9 months after accounting year-end. HMRC Corporation Tax: 12 months after accounting year-end. Late filing penalties apply immediately after deadline.
Even dormant companies must file accounts with Companies House. Must meet strict HMRC dormancy criteria. Still require iXBRL format for any statutory filings.
LLPs meeting the size thresholds or classified as traded companies must file accounts in iXBRL. However, many small LLPs remain exempt from full iXBRL requirements.
Unlike companies, small LLPs below thresholds may file simplified accounts without full iXBRL tagging.
Large LLPs: Full accounts in iXBRL format (mandatory). Medium LLPs: Full accounts in iXBRL format (mandatory). Small LLPs: Simplified accounts permitted (reduced tagging). Traded LLPs and banking LLPs must file full iXBRL regardless of size.
Turnover: Small: ≤ £10.2m | Medium: ≤ £36m | Large: > £36m
Balance Sheet: Small: ≤ £5.1m | Medium: ≤ £18m | Large: > £18m
Employees: Small: ≤ 50 | Medium: ≤ 250 | Large: > 250
LLPs qualifying for audit exemption may file abbreviated accounts, but must still use iXBRL format where size thresholds are exceeded.
Companies House: 9 months after accounting year-end. HMRC (if applicable): 12 months after accounting year-end for tax returns. Must exceed 2 of 3 criteria for two consecutive years.
Charitable companies must file accounts in iXBRL format following either FRS 102 or the Charities Statement of Recommended Practice (SORP), depending on their size and structure.
Follow standard company iXBRL requirements plus additional charity-specific tags. Must include Statement of Financial Activities (SOFA). Charity Commission annual return filed separately.
Income over £1m: Full iXBRL accounts. Income £250k-£1m: Simplified iXBRL. Income under £250k: Basic tagging only. Annual return to Charity Commission.
Charitable entities must use specialized iXBRL tags that accommodate charity-specific reporting including restricted funds, designated funds, and endowment reporting under FRS 102 and Charities SORP.
Companies House: 9 months after year-end. Charity Commission: 10 months after year-end. HMRC (if applicable): 12 months after year-end for Corporation Tax.
Public companies listed on UK exchanges have additional iXBRL requirements beyond standard statutory accounts, particularly for annual reports under the UK Single Electronic Format (UKSEF).
Statutory accounts in iXBRL format to Companies House. Corporation Tax returns to HMRC. All standard company filing obligations apply.
Complete annual reports in iXBRL format. Enhanced tagging for financial statements and narrative sections. Compliance with FCA and ESMA validation rules.
Detailed block-tagging of primary statements, notes, and disclosures. IFRS-compliant taxonomy with extensions as needed. ESMA quality validation.
Premium Listed: UKSEF mandatory from January 1, 2025. Standard Listed: UKSEF mandatory from January 1, 2026. AIM Companies: Voluntary adoption with incentives.
UK entities are classified by size using specific financial thresholds that determine the level of iXBRL tagging required and available exemptions.
Simplified iXBRL tagging only
Standard iXBRL tagging required
Detailed iXBRL + audit requirements
A company qualifies for a smaller category only if it meets at least 2 of the 3 criteria for the current year AND the preceding financial year. This prevents manipulation through one-off adjustments and ensures consistent classification.
While most UK entities must file in iXBRL, certain exemptions and special provisions apply to specific entity types and circumstances.
Unincorporated businesses file traditional tax returns (SA100, SA800) unless specifically required by sector regulations.
Foreign companies with UK branches may use alternative formats if filing equivalent information in their home jurisdiction.
Some specialized investment structures may qualify for alternative reporting frameworks.
Can file simplified dormant company accounts with minimal iXBRL tagging, but still must use structured format.
Below audit thresholds can file simplified accounts with reduced iXBRL requirements.
Can use simplified micro-entity accounts with reduced tagging requirements but still in iXBRL format.
Certain regulated sectors have additional or modified iXBRL requirements beyond standard company filing obligations.
Banks, building societies, and insurers have enhanced regulatory reporting requirements with sector-specific iXBRL taxonomies.
Registered social landlords must file using Housing SORP with specialized iXBRL tags for social housing activities.
Universities and colleges follow Education SORP requirements with additional iXBRL tagging for education-specific reporting.
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