Classical Insider Theory (Dirks Test)

The Classical Insider Theory, anchored in the Supreme Court's landmark 1983 Dirks v. SEC decision, establishes that liability under Rule 10b-5 and Section 16 attaches only when an insider breaches a fiduciary or similar duty of trust and confidence owed to the issuer and its shareholders. Under the Dirks test, a tipper violates securities law only if the tipper personally benefits, directly or indirectly, from the disclosure of material nonpublic information. Personal benefit includes financial gain, reputational benefit, or access to information reciprocity. Tippees become liable if they knew or should have known that the tipper breached a duty and received a personal benefit.

In quantitative insider-trading compliance and surveillance platforms, the Dirks test serves as the legal boundary for classifying trading signals and tipping networks. The framework requires platforms to assess not merely the fact of information flow but the intent and personal benefit structure underlying the disclosure. Scoring systems must distinguish between legitimate mosaic theory research, where analysts synthesize public information, and classical insider violations involving breached fiduciary duties. This distinction is critical for calibrating insider-activity concentration metrics and signal persistence across trading accounts linked to issuer personnel, board members, and service providers.