Claude Code skills · updated 2026-10-03

Trader Year-End Tax Skill

Paste your trades: see which losses count this year

trader-year-end-tax-check - findings on the bundled example

One pasted trade list returns a year-end checklist for the US, Germany, Japan, Brazil or Spain: which losses count, which a rule blocks or moves, the dated steps left and the arithmetic (worked example: -1,200.00 blocked by a Roth IRA buy 14 days later, -300.00 counts).

Get it on Whop - $19 once Get it on Gumroad

Who it's for

Built for self-directed traders in the US, Germany, Japan, Brazil and Spain who close positions before December 31.

What breaks, and when

A loss sold in December and bought back within 30 days is disallowed in the US; in Germany a missed 15 December request leaves a loss stuck at one bank.

The worked example it ships

YEAR-END CHECK - US - tax year 2026
Trades read: 5 · accounts: taxable, roth_ira

| # | Trade | Rule | What happens | Amount |
|---|---|---|---|---|
| 1 | Sold 100 XYZ on 2026-12-08 at 38.00 (bought 2026-08-04 at 50.00) | US wash sale (Pub 550): purchase within 30 days, IRA counts | Bought 100 XYZ in the Roth IRA on 2026-12-22 = 14 days after the sale -> loss DISALLOWED | -1,200.00 not deductible |
| 2 | Sold 50 ABC on 2026-11-17 at 14.00 (bought 2026-03-02 at 20.00) | US wash sale: window 2026-10-18 to 2026-12-17 | No ABC purchase in the window in any listed account -> loss COUNTS | -300.00 deductible |

Arithmetic
1) XYZ: (38.00 - 50.00) x 100 = -1,200.00. The Roth IRA buy is inside 2026-11-08 ... 2027-01-07 (30 days before and after 2026-12-08).
   Pub 550: the disallowed loss is added to the cost of the new shares. The new shares are in the Roth IRA - how that basis can be used there is outside this check; ask your adviser.
2) ABC: (14.00 - 20.00) x 50 = -300.00. Window checked: 2026-10-18 ... 2026-12-17 (30 days each side). No ABC buys found.

Losses that count for 2026 from this list: -300.00 (only ABC).

Dated steps for the rest of the year
- [ ] Until 2026-12-17 - do not buy ABC in any account (taxable, IRA, spouse) if you want the -300.00 to count (wash sale window).
- [ ] Check 2027-01-01 ... 2027-01-07 - the XYZ window runs into January; any further XYZ buy there is also inside it.
- [ ] Before filing - match this list with your broker's Form 1099-B, which may not see the Roth IRA purchase.

Not covered by this check: options, crypto, state taxes.
This is a calculation from the rules listed, not tax advice; check special cases with your tax adviser or your broker's tax report.

What you get

A findings table per trade with the rule and the amount
Dated steps for the rest of the year
The arithmetic for every number
Rules with official sources for 5 countries

Install

Unzip into ~/.claude/skills/ (Claude Code) or upload it as a custom skill in the Claude app, then ask: "Here are my 2026 trades. Which losses count before December 31? I am in the US.". Nothing to run.

unzip trader-year-end-tax-check.zip -d ~/.claude/skills/

Ask Claude

“Here are my 2026 trades. Which losses count before December 31? I am in the US.”

What it does not do

No buy or sell advice, no signals, no forecasts. Options, futures, crypto and church tax are not covered. A calculation from the listed rules, not tax advice.

FAQ

What is a Claude skill?

A folder with a SKILL.md, a method, fill-in templates and a worked example. Claude loads it when your request matches and follows that method instead of improvising.

How is this different from asking Claude without the skill?

The skill carries a fixed method, fill-in templates and a full worked example, so Claude follows the same structure every time instead of improvising a new one.

What does it not do?

No buy or sell advice, no signals, no forecasts. Options, futures, crypto and church tax are not covered. A calculation from the listed rules, not tax advice.

How do I install it?

What do I get when I buy?

The zip. On Whop it is in your library as a download lesson with the zip attached; on Gumroad it is the product file.