Complete FINRA Rules and Notices to Members are available at: http://www.finra.org

Below are some of the FINRA Rules that we advise you to review:

2110.   Standards of Commercial Honor and Principles of Trade
2120.   Use of Manipulative, Deceptive or Other Fraudulent Devices
2320.   Best Execution and Interpositioning
2460.   Payments for Market Making
3310.   Publication of Transactions and Quotations
IM-3310.  Manipulative and Deceptive Quotations
3320.   Offers at Stated Prices
IM-3320.  Firmness of Quotations
6600.   Reporting Transactions in over-the-counter Equity Securities
6620.   Transaction Reporting
6630.   Recording of Quotation Information
6700.   Reporting Transactions In Non-NASDAQ Securities
6740.   Submission of Rule 15c2-11 Information on Non-Nasdaq Securities
6750.   Minimum Quotation Size Requirements For OTC Equity Securities

NASD Notice to Members 92-50 should be reviewed because it discusses many issues relevant to the OTC equity market such as 15c2-11 and Best Execution (see excerpt).