Synthetic UK broker pack
Transaction, cash, and holdings CSVs; two quarterly statements; four contract notes; a dividend notice; and an ambiguous corporate-action example. The core documents reconcile to one hidden answer ledger.
Try it without using anyone’s financial records
Two downloadable packages let collaborators test different parts of the workflow. Everything is invented, conspicuously labeled, and contains no real person, account, broker, fund, or identifier.
Candidate PFIC reference cases
Community cross-checking openSix stated fact patterns with candidate Form 8621 fields, day-allocation workpapers, readable summaries, references, and blank validation records.
The second package is not being presented as a set of “correct filings.” The arithmetic is deterministic and internally tested, but every case remains
CANDIDATE_UNREVIEWED. There is no budget or plan to commission paid professional validation. The practical next step is for independent contributors to reproduce the calculations, publish their methods, and document disagreements. A qualified professional is welcome to help as a volunteer collaborator or investor, but that is optional.A useful test takes three separate passes
| Pass | Question | Answer key |
|---|---|---|
| 1. Extraction | Can the CSVs and PDFs be turned into source-linked facts without guessing? | Canonical synthetic ledger |
| 2. Reconciliation | Do purchases, reinvestments, sales, cash, and year-end units agree? | Expected normalized ledger and positions |
| 3. Tax and form mapping | Do independent calculations agree with the candidate section 1291 schedules and Form 8621 fields? | Candidate workpapers plus published independent reproductions |
Keep the source_truth and expected folders hidden during a blind document test. An LLM should not see or generate both the inputs and the answer. See the synthetic-example guide and the official Form 8621 instructions.
The journey in five steps
The private beta guides the user one question at a time. “Review page” means a private HTML questionnaire generated locally—not a person and not a hosted service.
Install the private application
An invited user downloads the private checkout and installs a local launcher. No cloud account, LLM, or model download is required for the deterministic calculations.
Create a separate private workspace
Program files, original broker records, and the generated calculation workspace live in separate folders. Names, SSNs, addresses, and full account numbers are not needed for the calculation stage.
Preserve and review source records
The tool hashes local PDFs and spreadsheets, inspects broker tables without printing rows, and creates guided mapping pages. Extracted or mapped facts remain unresolved until checked against the source.
Reconstruct and reconcile
Confirmed transactions build lots and basis. The reconstructed December 31 units must exactly match separately entered statement positions before draft form values are produced.
Export a review packet
The result is a traceable bundle: calculations, evidence references, unresolved questions, candidate Form 8621 values, and conspicuously incomplete drafts. It is never presented as ready to file automatically.
What to collect first
For an AJ Bell or similar UK investment account, start with four record groups for each account.
Transaction history
Purchases, sales, switches, redemptions, transfers, reinvestments, fees, and corporate actions—ideally from the earliest relevant acquisition.
Cash statement
Contributions, withdrawals, dividends, interest, charges, purchase payments, sale proceeds, and cash used for reinvestment.
Quarterly statements
Especially every statement covering December 31. These independently support holdings and values for each relevant year.
Contract notes and messages
Deal confirmations, dividend notices, transfers, fund mergers, conversions, splits, and other corporate actions.
Older records may require a direct request. If the online portal exposes only a limited history, download what is available immediately and ask the broker for its complete transaction and cash ledgers, older statements, contract notes, and transfer records. An earlier provider may be needed for investments transferred in specie.
Why “three years” can require older records
The Streamlined Domestic Offshore Procedures generally refer to three covered income-tax returns and six covered FBAR years. That filing window is different from the investment-history window needed to calculate those returns.
| Question | Possible earlier information |
|---|---|
| Was a distribution excessive? | Distributions from the three preceding tax years, or the shorter prior holding period. |
| What was the gain on a sale? | The original acquisition date, units, basis, and later lot activity—even when the purchase predates the amended-return period. |
| What is the section 1291 interest charge? | The gain allocation across the holding period, historical highest tax rates, and the IRS underpayment rate applicable in each quarter. Earlier interest rates were often lower than recent rates. |
Older records can therefore be calculation inputs without implying that every earlier income-tax return will be amended. Procedure selection, eligibility, PFIC classification, and filing decisions remain explicit review questions.
What the private beta produces
Reconciled ledgers
Transactions, lots, basis, distributions, dispositions, year-end positions, and correction histories.
Calculation reports
Per-share tests, holding-period allocations, documented exchange rates, historical tax-rate inputs, and interest calculations.
Decision brief
What is missing, why it matters, and the next concrete action—without treating a generic warning as an answer.
Draft form handoff
Candidate Form 8621 values, line explanations, intentionally blank lines, and incomplete draft PDFs tied to a verified local bundle.
Common questions
Does the hosted page process my records?
No. It contains general product information and fictional test fixtures only. There is no upload form, browser database, analytics dependency, calculation engine, or private application download here.
Does the application need an LLM?
No. The current deterministic workflow does not use an LLM for calculations or form mapping. Optional local assistance may later propose source facts, but proposals would still require source review.
Does it decide whether a fund is a PFIC?
No. PFIC classification, section 1291 treatment, elections, procedure eligibility, ownership, and uncertain accumulation-unit questions require explicit confirmation.
Are there sample statements I can use?
Yes. Download the synthetic UK broker pack above. It is generated from an invented ledger and includes CSV exports, statements, contract notes, and notices. It resembles the categories found on a UK investment platform but does not copy or claim to reproduce an AJ Bell export.
Are the sample PFIC forms known to be correct?
No. They are candidate field packets and workpapers, not filed returns. The project is seeking independent, reproducible community checks and will publish discrepancies. Paid professional validation is not planned. If a qualified international-tax professional volunteers or future funding supports review, that separate review will be labeled clearly.
How can I help validate the examples?
Choose one case, recompute it without using PFIC Catch-Up, and share your method or workpaper. Report any disagreement with a citation to the relevant form, instruction, statute, regulation, or rate table. A documented independent reproduction can strengthen a case without being described as professional advice or a correct filing.
Can a collaborator review the project?
Yes, if the project owner grants access to the separate private repository. The public walkthrough deliberately contains no application source, release archive, private repository link, or real-data example.