Operational: Practical Implementation Module 15: 8966 Walkthrough Lesson 5: Form 8966 Walkthrough Part 3 Lesson 5: Form 8966 Walkthrough Part 3 In Lesson 5, we pick up with Line 5 of Form 8966 requiring the taxpayer identification number of the filer, the global intermediary identification number (GIIN), or other taxpayer identifying numbers of the filer. Lesson Resources Video Transcript Audio Previous Lesson Back to Module Next Lesson