Authority of the GAAP Financial Reporting Taxonomy (GRT)
Preparers using GAAP for publicly traded companies are required not only to create financial statements, but also to assign an eXtensible Business Reporting Language (XBRL) tag to every number, table, accounting policy, statement, and note.
In 2010, the Financial Accounting Foundation (FAF) and the Financial Accounting Standards Board (FASB) assumed ongoing development and maintenance responsibilities for the GAAP Financial Reporting Taxonomy (Taxonomy), which was originally developed by XBRL US, Inc. under contract to the U.S. Securities and Exchange Commission (SEC). The Taxonomy is applicable to public issuers registered with the U.S. Securities and Exchange Commission (SEC).
Structure of the taxonomy
A taxonomy is a framework that standardizes the representation of financial concepts. Different taxonomies cater to various reporting requirements, such as U.S. GAAP, IFRS, or industry-specific standards.
The U.S. GAAP Financial Reporting Taxonomy (Taxonomy) is a list of computer-readable tags in XBRL format. The Taxonomy allows companies to tag and depict relationships among facts that are included in typical long-form financial statements and related disclosures. The tags allow computers to automatically search for information and assemble data so those data can be readily accessed and analyzed by consumers of financial data such as investors, analysts, and others. More information about the taxonomy can be found here.
Information in a filing
XBRL filings consist of three main components: instance documents, schemas, and linkbases. Instance documents contain the actual financial data, schemas define the elements and their relationships, and linkbases provide context, such as calculations, definitions, and labels.
More details on the structure and content of a filing are available here: https://www.sec.gov/newsroom/whats-new/updated-edgar-extensible-business-reporting-language-xbrl-guide-available
Details about our algorithm
Because the FASB periodically revises and updates its taxonomy, these FASB-defined calculation linkbases may differ from year to year. The taxonomy version referenced in the filing is used to match the tagged values in the filing to the appropriate version of the taxonomy.
Our algorithm does not rely on the linkbases that are contained in the filing. Instead, it is based on the calculation linkbases specified by the FASB. The two most recent calculation linkbases are available on the FASB website in XBRL and Excel formats. These may be downloaded from the FASB website https://www.fasb.org/projects/fasb-taxonomies. Older versions of calculation linkbases are no longer available at the FASB’s website, but we provide a copy of them in Excel format below.
The algorithm is simple because it relies on the structure of the FASB taxonomy and FASB-provided calculation linkbases for the three primary statements of non-financial companies—specifically, Statement of Financial Position [104000], Statement of Income [124000], and Statement of Cash Flows [152200]—to extract values directly from data filed with the SEC. When a parent value is missing, the relationships specified in these linkbases are used to construct parent values from child values.
Algorithmic approaches have the advantage of avoiding human intervention and manual collection of data. Our algorithm is simple to implement, but this simplicity comes at the cost of ignoring information about the structure of a particular financial statement contained in filer-provided linkbases. For instance, if a company tags values on a statement in a manner inconsistent with the FASB-provided calculation linkbase for the FASB-provided statement, the algorithm can result in a value that is inconsistent with the human-readable value on the face of the financial statement.
For each of the three primary financial statements, the FASB provides multiple calculation linkbases that define the arithmetic relationships among tags applicable to each statement. Each linkbase is identified by an index number following its name. For example, the income statement calculation linkbase we used in the algorithm has an index number of 124000. The imputed tag may vary depending on the selected calculation linkbase. To ensure consistency in tag value imputation, we use the linkbase most appropriate for non-financial companies for each financial statement, as previously described.
However, filers are not required to tag their financial statement figures using tags from the same calculation linkbase. When filers choose tags from different calculation linkbases, the algorithm may impute a tag value that differs from the human-readable value presented in the financial statement.
Archive of Historical US GAAP Taxonomies (Source: FASB)
In processing as-fled data, we relied on the annual U.S. GAAP taxonomies starting 2009 from the FASB’s website. However, recently we noticed that the FASB has stopped providing historical taxonomies on its website. To facilitate follow-up research, we are providing an archive of historical and current taxonomies starting 2009, with the exception of 2010 as we could not locate a version for that year.
Disclaimer: Researchers should exert caution when using these taxonomies. We do not assume any responsibility for potential errors or inconsistencies contained in these files.