For fundamental investors probably the most important financial information to study are the financial reports from companies that they wish to potentially invest in. For publicly traded companies in the US, the SEC regulates what data needs to be reported and at which frequency, and investors typically access those financial reports through their own brokerage firm’s website, or through publicly available databases from other Internet providers. In addition, all the original filings from all companies are also directly available from the SEC in the EDGAR database. In addition to HTML and PDF versions of those financial reports, the EDGAR database also contains XBRL versions of those company filings since 2007, with the intent of making this data more easily comparable and directly consumable by computer programs for further analysis.

At least that is the goal…

In this article we’re going to look at some issues with the XBRL data quality of company filings in the SEC’s EDGAR database and show the surprising lack of correlation of high-level financial data extracted from the XBRL filings with publicly available financial data about US companies provided, e.g., by Yahoo Finance, Google Finance, and Fidelity Investments, as well as the shocking discrepancies found in the data reported by those separate services amongst one another.

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