http://www.form4oracle.com/investing-with-insider-trading/insider-trading-faq

General Transaction Codes

• P: Open market or private purchase of non-derivateive or derivative security
• S: Open market or private sale of non-derivative or derivative security
• V: Transaction voluntarily reported earlier than required

Rule 16b-3 Transaction Codes

• A: Grant, award or other acquisition pursuant to Rule 16b-3
• D: Disposition to the issuer of issuer equity securities pursuant to Rule 16b-3
• F: Payment of exercise price or tax liability by delivering or withholding securities incident to the receipt, exercise or vesting of a security issued in accordance with Rule 16b-3
• I: Discretionary transaction in accordance with Rule 16b-3 resulting in acquisition or disposition of issuer securities
• M: Exercise or conversion of derivative security exempted pursuant to Rule 16b-3