The staff in the Commission’s Division of Economic and Risk Analysis (DERA) recently analyzed custom tags used in eXtensible Business Reporting Language (XBRL) filings submitted by issuers to comply with the rules requiring financial statement information to be reported in XBRL. Our analysis covered XBRL filings submitted in Forms 20-F, 20-F/A, 40-F and 40-F/A for fiscal years 2019 through 2021 by filers preparing their reports using International Financial Reporting Standards as issued by the International Accounting Standards Board. The purpose of the analysis was to analyze trends in filers’ use of custom tags in their XBRL financial data for the aforementioned forms during the last three years in two categories: 1) financial statements (F/S) only and 2) F/S and notes.
The Commission’s rules allow filers to create custom tags when the standard taxonomy does not provide an appropriate element to tag the disclosure. While this customization accommodates unique circumstances in a filer’s particular disclosure, the Commission has acknowledged that the use of custom tags could potentially reduce the comparability of inter-company data. Thus, the Commission’s rules specify the limited circumstances under which a filer may create custom tags.
Custom tag rates on only the financial statements saw a modest increase in 2021, but the overall custom tag rates for financial statements and footnotes combined decreased in 2021. This decrease reverses the trend observed since 2017 when the overall custom tag rates steadily increased each year through 2020.
DERA staff intends to continue reviewing filers’ use of XBRL custom tags in their submissions to the Commission. Depending on the results of those efforts, DERA staff may share additional trends, issue guidance, or pursue other actions.
For the staff observations DERA staff published in 2014 on custom tag rates, see http://www.sec.gov/dera/reportspubs/assessment-custom-tag-rates-xbrl.html. For the staff’s previous trend analyses on custom tags, see the Trends section on this page: https://www.sec.gov/structureddata/osdstaffobsandguide. DERA staff welcomes your questions and comments. Please feel free to email us at StructuredData@sec.gov or leave us a voicemail at (202) 551-5494.
 Release No. 33-9002 (Jan. 30, 2009), 74 FR 6776 (Feb. 10, 2009) and Release No. 33-10514 (Jun. 28, 2018).
 Fiscal years are based on filers’ self-designations. Our analysis includes custom tags of line item tags and excludes tags that are abstract, member, domain, and related to the document and entity. For definitions of abstract, member, and domain, see XBRL glossary at https://www.sec.gov/page/osd_xbrlglossary. Document and entity tags are largely related to identification of filings and filers including, for example, form type, company name, filer size, and public float.
 17 CFR 232.405(c)(1)(iii).
 See pages 104-105 of Release No. 33-9002 (Jan. 30, 2009).
 See 17 CFR 232.405(c)(1)(iii)(B) (“An electronic filer must create and use a new special element if and only if an appropriate tag does not exist in the standard list of tags for reasons other than or in addition to an inappropriate standard label.”).
Modified: April 6, 2023