I build Intrinsiqq, which computes quality scores, valuations and ten years of financials for around 7,800 listed companies. Every number comes from companies' own filings with the SEC.
People assume the hard part was the finance. It was not. The hard part was that financial filing data is free, structured, machine readable, and constantly, quietly wrong in ways that do not announce themselves.
I want to describe the shape of that problem, because I have not seen it written down anywhere and I would have saved months if someone had.
Why build on filings at all
Most finance sites buy aggregated data from a vendor. I went to the source instead, because filings are free, public, legally usable, and they contain what a company actually told a regulator rather than a vendor's cleaned-up interpretation. It means the numbers on my site reconcile with the annual report, and it is the reason the product can be free at all. I wrote up how the pipeline fits together if you want the overview.
