The Virginia legislature is doing a study on unitary taxes for brother/sister or parent subsidiary corporations. https://www.tax.virginia.gov/news/corporate-unitary

This study requires corporations to file a special return by July 1, 2021 based upon their 2019 tax returns.

Corporations must be “unitary businesses”.

“”Unitary business” means a single economic enterprise made up either of separate parts of a single business entity or of a commonly controlled group of business entities that are sufficiently interdependent, integrated, and interrelated through their activities so as to provide a synergy and mutual benefit that produces a sharing or exchange of value among them and a significant flow of value to the separate parts. A “unitary business” includes that part of the business that meets the definition in this section and is conducted by a taxpayer through the taxpayer’s interest in a partnership, whether the interest in that partnership is held directly or indirectly through a series of partnerships or other pass-through entities. A “unitary business” shall not include persons subject to, or that would be subject to if doing business in the Commonwealth, the insurance premiums license tax under Chapter 25 (§ 58.1-2500 et seq.), Code of Virginia, or the bank franchise tax under Chapter 12 (§ 58.1-1200 et seq.)”

So, talk to your tax advisor if this applies to you.