When is a foreign corporation excluded from a California water's edge combined report?

Who is in a water's edge group

The water's edge election replaces worldwide combined reporting with a combined report limited to the entities Revenue and Taxation Code Section 25110 describes. The categories that decide most cases: corporations incorporated in the United States, wherever they operate, are included, except those electing under sections 931 through 936 of the Internal Revenue Code (Section 25110(a)(1)(C)); and any corporation other than a bank, regardless of the place where it is incorporated, is included if the average of its property, payroll, and sales factors within the United States is 20 percent or more (Section 25110(a)(1)(B)). The statute reaches domestic international sales corporations and export trade corporations as well, but the 20 percent test is where a foreign operating company's inclusion is usually decided.

Two partial inclusion rules then qualify the exclusion. A foreign corporation below the threshold is nonetheless included to the extent of its income derived from or attributable to sources within the United States and its factors assignable to a location within the United States (Section 25110(a)(2)(A)(i)), which the regulations measure by effectively connected income concepts. And a controlled foreign corporation with Subpart F income is included to the extent determined by multiplying its income and factors by the ratio of its Subpart F income to its current earnings and profits (Section 25110(a)(2)(A)(ii)). Exclusion from the group is therefore never the end of the analysis; it is the frame within which the two overlays are tested.

The 20 percent test

The test averages three factors, property, payroll, and sales, computed on a United States basis against the corporation's worldwide denominators. Although California apportions income under a single sales factor, the three-factor average continues to govern this inclusion test. The Franchise Tax Board reached the analogous conclusion when the formula first moved away from equal weighting, in the double-weighted sales era (Legal Ruling 95-5); that ruling predates the single sales factor and serves as historical support rather than a holding on today's formula, but the 20 percent test is defined by its own statutory text, which has not changed. Two computational rules decide close cases. First, a factor the corporation does not have on a worldwide basis is disregarded, and the average is taken over the factors that remain (Cal. Code Regs. tit. 18, § 25110(d)(2)(B)2). A corporation with no property or payroll anywhere is measured on its sales factor alone, while a corporation with worldwide property and payroll but none in the United States averages two zeros against its United States sales percentage. The arithmetic rewards real operations outside the United States: significant United States sales divided across three factors can still produce an average below 20 percent. Second, sales made by the foreign corporation to members of the water's edge group are excluded from both the numerator and the denominator of its sales factor (Cal. Code Regs., tit. 18, section 25110(d)(2)(B)3.d), which can move the percentage in either direction and should be computed, not assumed.

The effectively connected income overlay

The partial inclusion rule for United States source income is measured by effectively connected income, with two modifications that matter. Effective connection is determined under the Internal Revenue Code, but provisions of United States income tax treaties that would limit the application of the effectively connected income rules are not followed (CCR § 25110(d)(2)(F)1.a). A foreign corporation that relies on a permanent establishment article to escape federal net-basis taxation cannot rely on it for California; the question is whether the income is effectively connected under the Code alone. In addition, certain foreign source income that the Code deems effectively connected is included as well (CCR § 25110(d)(2)(F), incorporating IRC Section 864(c)(4)(B)). The operative sequence for a foreign service provider is therefore federal in form but broader in result: identify whether the corporation is engaged in a United States trade or business, classify its income under the Section 864 rules, and disregard the treaty. Income that is not effectively connected under that analysis, for example fees for services performed entirely outside the United States, does not enter the combined report of an excluded foreign corporation, unless it arises from a contract a principal purpose of which was the avoidance of federal or California tax (Cal. Code Regs., tit. 18, section 25110(d)(2)(F)1.b).

Why the answer can be the minimum tax

The mismatch between the inclusion rules and California's sourcing rules is the planning engine, and it runs in both directions. California sources receipts from services to the location of the customer's benefit, and receipts from asset management services to the domicile of the investors, under the market-based sourcing regulations (CCR § 25136-2(j)(3), making the amendments applicable to taxable years beginning on or after January 1, 2026, and CCR § 25137-14 for mutual fund service providers). Those receipts can make a foreign corporation a California taxpayer under the doing business thresholds of Revenue and Taxation Code Section 23101(b) even with no United States presence. But once that corporation elects water's edge, the measure of its tax is built from the combined report Section 25110 describes, and its own income enters that report only through the 20 percent test and the partial inclusion overlays. A foreign corporation below the factor threshold, with no effectively connected income and no Subpart F inclusion, files Form 100W with a measured tax at or near zero, and pays the minimum franchise tax. The corporation is a taxpayer, the return is due, and the election must be valid; what changes is the measure.

Election mechanics

The election is made on an original, timely filed return for the year of election, computed consistently with a water's edge election and accompanied by the prescribed notification (Revenue and Taxation Code Section 25113(a)). Every taxpayer member of the self-assessed group must elect. The commitment is real: the election remains in effect until terminated, may not be terminated without Franchise Tax Board consent until it has been in effect for at least 84 months, and after termination another election is barred for taxable years beginning within the following 84 months (Section 25113(c)). A foreign affiliate that later becomes a California taxpayer in its own right does not silently break the group's election; Rev. and Tax. Code section 25113(b)(4) and (b)(5) deem it to have elected with the group in defined circumstances, including a foreign-incorporated unitary affiliate that becomes a taxpayer solely under the doing business thresholds of section 23101(b) in a taxable year beginning on or after January 1, 2021, but the conditions are specific and the affiliate's filing posture should be confirmed rather than assumed.

Practice notes

The record that substantiates the position has three parts. First, the factor computation: the 20 percent test is computed entity by entity and year by year, and United States payroll or property added for commercial reasons can move a corporation across the threshold in a later year, so the computation belongs in the annual workpapers rather than in the planning memo alone. Second, the effectively connected income analysis: the conclusion that the corporation has no United States trade or business should be documented under the Code rules on their own terms, because the treaty that protects the federal position does not protect the California one. Third, the election itself: the validity, scope, and age of the election decide every downstream answer, and the 84-month commitment means the structure must make sense across the full election period, not only in the year it is designed. G&G State Tax Group provides water's edge group composition and foreign affiliate inclusion analysis alongside its state and local tax practice.