wealthschema / benchmark / items / fb-wash-0007
ITEM PROVENANCE · WASH-SALE-MECHANICS

fb-wash-0007

status: publishedversion: v1corpus: 2026.9key: derivedseverity: high
Scenario (all facts stipulated)
{
  "facts": "On March 10, 2026, a taxable account sells 200 shares of PQR common stock at a loss. On April 8, 2026 — 29 days after the sale — it buys 200 shares of the same PQR common stock. There are no other PQR transactions in 2026. The taxpayer is not a dealer.",
  "sale_date": "2026-03-10",
  "repurchase_date": "2026-04-08",
  "shares_sold": 200,
  "replacement_shares": 200
}
Question posed to the model under test

How does section 1091 treat the realized loss on the March 10 sale? Answer with exactly one option id.

Answer options
  • loss-disallowed-fullyThe loss is disallowed in full
  • loss-disallowed-partiallyThe loss is disallowed in part
  • loss-fully-deductibleThe loss is fully deductible
  • no-loss-nothing-to-disallowThere is no loss, so section 1091 does not apply
Answer key

loss-disallowed-fully

Derivation from the cited text

The statutory window runs 30 days before through 30 days after the March 10 sale, so it closes at the end of April 9, 2026. The April 8 repurchase falls 29 days after the sale, inside the window, and the 200 replacement shares match all 200 sold shares. Under section 1091(a), no deduction is allowed for the loss.

Rubric

Selects loss-disallowed-fully; the repurchase is inside the 61-day window and fully matched.

Cited primary sources (quote-gated)
within a period beginning 30 days before the date of such sale or disposition and ending 30 days after such date, the taxpayer has acquired (by purchase or by an exchange on which the entire amount of gain or loss was recognized by law), or has entered into a contract or option so to acquire, substantially identical stock or securities, then no deduction shall be allowed

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
within a period beginning 30 days before the date of such sale or disposition and ending 30 days after such date, the taxpayer has acquiredusc-1091

The key is correct. Initial logic and parameters are validated. The April 8 repurchase occurs 29 days after the March 10 sale, falling within the statutory 30-day window, resulting in full disallowance of the loss.

deepseek-v4-proagrees the key is correctquote matched
within a period beginning 30 days before the date of such sale or disposition and ending 30 days after such date, the taxpayer has acquired (by purchase or by an exchange on which the entire amount of gain or loss was recognized by law), or has entered into a contract or option so to acquire, substantially identical stock or securities, then no deduction shall be allowedusc-1091

April 8, 2026, is 29 days after March 10, 2026, so the reacquisition is within the 30-day statutory window. The replacement is 200 shares of the same PQR common stock, matching all 200 shares sold, so the realized loss is disallowed in full under §1091(a). The taxpayer is not a dealer, so no dealer exception applies.

Version history & errata

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