Unless a exception is available, broker-dealers must report over-the-counter transactions in equities, both NMS Securities and "OTC Equity Securities" to FINRA on one of the various FINRA "Trade Reporting Facilities." OTC transactions in NMS stocks are primarily reported either pursuant to the 6300A and 7200A Series Rules (the FINRA/Nasdaq Facility) or pursuant to the 6300B and 7200B Series Rules (the FINRA/NYSE Facility). Both sets of Rules are essentially identical. In addition, firms ay also report these transactions on the Alternative Display Facility pursuant to the 6200 and 7100 Series of Rules.
Transactions in OTC Equity Securities (non-NMS stocks including OTC Markets securities, ADRs, foreign securities, non-exchange listed DPP securities and Rule 144A securities are reported pursuant to the Rule 6620 and 7300 Series (the Order Reporting Facility or "ORF"). See FINRA Trade Reporting FAQ.
The 6100 Series of FINRA Rules is also relevant to trade reporting, most significantly Rule 6182 as to the reporting of short sales.