When this guide is useful
Related entities share people or services and transfer money without consistent invoices.
The distinction that matters
Identify actual work, contractual responsibility and the accounting entry in both entities. A payment label does not prove the charge reflects a genuine service.
A worked situation to investigate
An operating company pays a management entity while payroll and vendor costs are still split between their bank accounts.
The example is illustrative. Begin with the underlying event and its source documents, then separate missing facts from disagreements about their treatment. Work through the checks below in the order that matches your file, rather than treating a completed checklist as a tax conclusion.
Build a traceable handoff
Identify the affected person, entity or property and the relevant period. Keep original evidence, corrections and the reviewer's written conclusion connected. If the facts change after review, preserve the earlier version and ask whether the change affects implementation.