fb-wash-0024
{
"facts": "On November 9, 2026, a taxable account sells 80 shares of RST common stock for $41.00 per share; the basis is $50.00 per share. On November 24, 2026 it buys 80 shares of RST for $39.00 per share. There are no other RST acquisitions within 30 days before or after the sale.",
"shares_sold": 80,
"sale_proceeds_per_share": 41,
"basis_per_share": 50,
"replacement_shares_in_window": 80,
"replacement_cost_per_share": 39
}What is the per-share basis of the 80 replacement shares after the wash-sale basis adjustment of section 1091(d)? Respond with the numeric amount only.
48 USD (tolerance ±0.01)
Produced by compute washsale.replacement-basis-per-share 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.
All 80 shares are washed; each replacement share carries its $39.00 cost plus the $9.00-per-share disallowed loss — $48.00 per share, within a cent.
“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”
“then the basis shall be the basis of the stock or securities so sold or disposed of, increased or decreased, as the case may be, by the difference, if any, between the price at which the property was acquired and the price at which such substantially identical stock or securities were sold or otherwise disposed of”
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.
“then the basis shall be the basis of the stock or securities so sold or disposed of, increased or decreased, as the case may be, by the difference, if any, between the price at which the property was acquired and the price at which such substantially identical stock or securities were sold or otherwise disposed of.” — usc-1091
The replacement shares were acquired at $39 per share, $2 below the $41 sale price. Under subsection (d), the $50 basis of the sold shares is therefore decreased by $2, yielding a replacement basis of $48 per share. All 80 sold shares were replaced within the stated window, so the calculation applies to all 80 replacement shares.
“then the basis shall be the basis of the stock or securities so sold or disposed of, increased or decreased, as the case may be, by the difference, if any, between the price at which the property was acquired and the price at which such substantially identical stock or securities were sold or otherwise disposed of.” — usc-1091
The November 9 sale is at a per-share loss (basis 50 vs. proceeds 41) and the November 24 repurchase of an equal number of RST shares falls inside the 30-day window of 1091(a), so the loss is disallowed and 1091(d) adjusts the replacement basis. Applying 1091(d) per share: basis of the shares sold (50) decreased by the difference between acquisition price of the replacement property (39) and sale price of the identical stock (41) yields 50+(39-41)=48, equivalently replacement cost plus disallowed loss, 39+(50-41)=48. The key value 48 is therefore the correct per-share replacement basis.
v1; no errata. Demonstrate a key error and the correction is published here, credited — challenge policy.