Staff from the SEC’s Division of Economic and Risk Analysis (DERA) have published the trend of custom tag usage in XBRL submissions for financial reporting in accordance with International Financial Reporting Standards (IFRS) and US Generally Accepted Accounting Principles (US GAAP) from fiscal years 2018 through 2020. When the standard XBRL taxonomy does not provide an appropriate element to tag the disclosure, the SEC’s rules allow filers to create custom tags. This modification accommodates special circumstances in a filer’s particular disclosure, but the SEC has recognized that using custom tags could potentially decrease the comparability of inter-company data. For this reason, the SEC’s rules specify the limited circumstances under which a filer is permitted to create custom tags.
For IFRS filings, the assessment performed by DERA was done to analyze trends in filers’ use of custom tags in XBRL financial data for Forms 20-F, 20-F/A, 40-F and 40-F/A. The two categories focused on were: 1) financial statements only and 2) financial statements and notes. From 2018 to 2019, custom tag rates saw slight increases both for financial statements only and when combining financial statements and footnotes. This trend of modest increase continued in 2020.
DERA staff also evaluated trends in filers’ use of custom tags in XBRL submissions for US GAAP filings for Forms 10-K and 10-K/A. The analysis for these forms found that in 2020, an increase occurred in the average custom tag rates for filers across each status compared to 2019. This indicates a reversal of the decrease from 2018 to 2019 (not including smaller reporting companies, which have seen steady increases in the average custom tag rate since 2018).
DERA staff will continue reviewing filers’ use of XBRL custom tags in their submissions to the SEC, and depending on findings, DERA staff may share additional trends, issue guidance, or pursue other actions. To view additional Staff Observations, Guidance, and Trends, visit sec.gov.