All data used is publicly available via the SEC. The following contains useful links and information about SEC registered companies.
(Add 13F to the filing category field to find companies that have filed 13F filings)
(Bulk data via the SEC)
(Bulk data via the SEC)
(Bulk data via the SEC)
(Explanations for different form types)
(Search database for companies, created by wallstreetlocal, formatted in BSON)
(Gist listing popular filers, taken from various sources. This is where the popular filers page gets its list from.)
(Gist listing top filers, taken from various sources. This is where the top filers page gets its list from.)
While not all data collected and formatted by wallstreetlocal is available by bulk because of data costs, you can download resources for individual filers by visiting their respective pages.