fb-rmd-0009

status: publishedversion: v1corpus: 2026.9key: computedseverity: medium

Scenario (all facts stipulated)

{
  "account_type": "traditional IRA (owner's lifetime distribution)",
  "age_at_year_end": 90,
  "beneficiary_context": "surviving spouse is not the sole designated beneficiary",
  "note": "The owner attains age 90 by December 31 of the distribution calendar year."
}

Question posed to the model under test

What is the applicable denominator (the Uniform Lifetime Table divisor) for this owner's required minimum distribution for the distribution calendar year? Respond with the numeric value only.

Answer key

12.2 years (tolerance ±0)

Produced by compute rmd.uniform-lifetime-denominator in src/lib/fiduciarybench/keys/index.ts — the stored value is machine-checked against the compute on every build; it cannot drift from its own code.

Rubric

The exact Uniform Lifetime Table entry for age 90.

Cited primary sources (quote-gated)

26 CFR § 1.401(a)(9)-9 · (c)

“the Uniform Lifetime Table, sets forth the applicable denominator that applies for lifetime distributions to an employee in situations in which the employee's surviving spouse is not the sole designated beneficiary”

Each quoted passage is exact-matched, after typographic normalization, against the corpus text fetched from the issuing authority (hashes in the corpus manifest). An item whose quote stops matching fails the build.

Verification record

generator: claude-fable (session 2026-09-01)disagreements: 0controls: fb-2026-09-a (5/5 caught)adjudicated by: — (none required or pending)

gemini-3.1-pro-previewagrees the key is correctquote matched

“The following table, referred to as the Uniform Lifetime Table, sets forth the applicable denominator that applies for lifetime distributions to an employee in situations in which the employee's surviving spouse is not the sole designated beneficiary.” — cfr-1-401a9-9

The scenario specifies that the owner is taking lifetime distributions, is age 90 at year end, and the surviving spouse is not the sole designated beneficiary. According to the Uniform Lifetime Table in paragraph (c), the applicable denominator for an employee of age 90 is 12.2. The key correctly identifies this value.

deepseek-v4-proagrees the key is correctquote matched

“The following table, referred to as the Uniform Lifetime Table, sets forth the applicable denominator that applies for lifetime distributions to an employee in situations in which the employee's surviving spouse is not the sole designated beneficiary.” — cfr-1-401a9-9

The scenario uses the Uniform Lifetime Table because the surviving spouse is not the sole designated beneficiary. The source's Table 2 to Paragraph (c) lists age 90 as having an applicable denominator of 12.2, so the key value is correct.

Version history & errata

v1; no errata. Demonstrate a key error and the correction is published here, credited — challenge policy.