This is the sixth entry in the Spotlight On series published by the CERT® Insider Threat Center. Each entry focuses on a specific area of threat to organizations from their current or former employees, contractors, or business partners and presents analysis based on hundreds of actual insider threat cases cataloged in the CERT insider threat database. This entry in the series focuses on insiders who stole intellectual property (IP), such as source code, scientific formulas, engineering drawings, strategic plans, or proposals, from their organizations to benefit a foreign entity. This technical note defines IP and insider theft of IP, explains the criteria used to select cases for this examination, gives a snapshot of the insiders involved in these cases, and summarizes some of the cases themselves. Finally, it provides recommendations for mitigating the risk of similar incidents of insider threat.