Subpart F CFC Flag Checklist

Caller independently verified ownership/control/income-category SubpartF criteria, no CFC conclusion from one percent. Independently declared positive evidence requirements; overlapping/unknown classes retained. Caller independently establishes matching units, evidence, method edition and applicability; output is not compliance, diagnosis, work-safety approval, geological identity or validated hazard prediction.

Description

Subpart F and controlled-foreign-corporation reviews use multiple ownership, control, and income facts.

Subpart F and controlled-foreign-corporation reviews use multiple ownership, control, and income facts.^[1]

This tool evaluates explicit positive evidence requirements while retaining uncertainty and overlapping classes.

When to use Subpart F CFC Flag Checklist

Use this tool when you need to review whether explicit class requirements are contradicted or fully witnessed. Establish jurisdiction, tax year, applicable authority, and eligible amounts or evidence before entering values.

How to use Subpart F CFC Flag Checklist and understand its results

Establish jurisdiction, tax year, applicable authority, and eligible amounts or evidence before entering values.
Enter callerSubpartFCfcClassIds, callerSubpartFCfcRequiredEvidence, observedSubpartFCfcEvidence, knownSubpartFCfcEvidenceFlags, following the field table and rules below, then run the tool.
Read compatibleCallerClasses, fullyWitnessedCallerClasses. Use the output meanings below to interpret units, signs, flags, and any nested result fields.
Correct reported input issues and run again. For a successful result, check the stated evidence coverage and assumptions before using it in your review.

Input field	Meaning	Value type	Requirement
callerSubpartFCfcClassIds	Caller subpart f cfc class ids	list of string	Required
callerSubpartFCfcRequiredEvidence	Caller subpart f cfc required evidence	numeric matrix	Required
observedSubpartFCfcEvidence	Observed subpart f cfc evidence	list of number	Required
knownSubpartFCfcEvidenceFlags	Known subpart f cfc evidence flags	list of number	Required

Provide unique nonblank class IDs, a nonempty rectangular binary requirements matrix with one row per class and one column per evidence item, aligned binary observed and known flags, and at least one required positive witness per class. A required known-zero observation contradicts a class. Unknown requirements leave it compatible but not fully witnessed. Return all compatible and all fully witnessed class IDs in supplied order; a zero requirement means that column is ignored, not a required negative fact.

compatible_c=∀j(required_cj=0 or known_j=0 or observed_j=1); witnessed_c=∀j(required_cj=0 or (known_j=1 and observed_j=1))

Symbols follow the input and output meanings and the calculation rules above.

Output field	Meaning	Value type
compatibleCallerClasses	Compatible caller classes	list of string
fullyWitnessedCallerClasses	Fully witnessed caller classes	list of string

json

{
  "input": {
    "callerSubpartFCfcClassIds": [
      "a",
      "b"
    ],
    "callerSubpartFCfcRequiredEvidence": [
      [
        1,
        0
      ],
      [
        0,
        1
      ]
    ],
    "observedSubpartFCfcEvidence": [
      1,
      0
    ],
    "knownSubpartFCfcEvidenceFlags": [
      1,
      0
    ]
  },
  "output": {
    "compatibleCallerClasses": [
      "a",
      "b"
    ],
    "fullyWitnessedCallerClasses": [
      "a"
    ]
  }
}

Limitations and assumptions

These are user-defined positive-evidence screens. Multiple classes may remain, no class may qualify, and missing evidence must be resolved independently. Fully witnessed requirements do not establish that the supplied classification rules are legally or scientifically complete.

Missing required fields, unknown fields, wrong types, and violated calculation rules are input issues. Numeric values must be finite; nonfinite results are rejected. Evidence arrays must be dense, with no missing cells. Numeric observation lists allow at most 10,000 entries, subject to any smaller bounds stated above. String lists allow at most 128 strings of at most 128 characters. Numeric matrices are limited to 128 rows and 128 entries per row, with rectangularity required where stated.

Alternative or Complementary methods

For a related review, use Tax Treaty Tie Breaker Article Lookup: Treaty residence tie-breakers belong to a particular country pair and treaty or protocol edition. This lookup preserves your verified article record and its residency-fact context. For a complementary step, use FEIE Foreign Earned Exclusion Limit Lookup: A foreign-earned-income exclusion limit needs the tax year, income definition, and qualifying facts. This lookup returns your independently verified record without establishing qualification.

References

Subpart F CFC Flag Checklist — tool.io

Similar or alternative tools

Tax Treaty Tie Breaker Article Lookup
Treaty residence tie-breakers belong to a particular country pair and treaty or protocol edition. This lookup preserves your verified article record and its residency-fact context.
FEIE Foreign Earned Exclusion Limit Lookup
A foreign-earned-income exclusion limit needs the tax year, income definition, and qualifying facts. This lookup returns your independently verified record without establishing qualification.