A Checklist of substantive defenses counsel should consider asserting when faced with an insider trading claim under Section 10(b) of the Securities Exchange Act of 1934 (Exchange Act) and its implementing regulation, Rule 10b-5. This Checklist covers common substantive defenses, including insufficient evidence supporting one or more elements of a claim, mosaic theory, the safe harbor rule for Rule 10b5-1 trading plans, reliance on counsel, no knowledge of confidentiality, and public disclosure of information.