Global wealth, tax exposure and estate planning, managed in one place. See how travel plans, where you live and the scenarios you’re weighing play out across your assets, entities, structures, business interests and investments — to optimize and protect what you’ve built as you live a global, sovereign life.
Most globally mobile entrepreneurs run their affairs across a lawyer’s inbox, an accountant’s spreadsheet, a broker’s statement and a drawer of PDFs. No single place holds the whole picture, so ordinary questions become projects: How many US days do I have left this year? Did we file the 2024 CIT? What is this actually worth net of the mortgage? Which entity owns the apartment?
Each answer arrives days later, assembled by hand, and rests on somebody’s memory rather than a document. That is expensive when it is merely slow, and dangerous when a residency threshold or a filing deadline passes unnoticed.
Every jurisdiction you touch, from a travel log you keep once — including the US substantial-presence test, weighted and projected against travel already booked.
Departure tax modelled against your own holdings — Canada’s deemed disposition, the US mark-to-market on expatriation — beside a guide to the exit-tax regime of nineteen jurisdictions, with the countries you actually hold residence or citizenship in marked against it.
A ledger of every return, receipt and working paper, filed against the entity and the year it belongs to, with lead times on every deadline and the filed copy attached as proof.
Corporations, foundations and trusts drawn as the structure they actually form — charters, registers, agents and standing, with the ownership map kept current.
Every transaction between you, your entities and connected parties recorded once — amount, currency, funding and the document that evidences it. The reportable categories and the reconciliation to each set of books fall out of the ledger.
Positions, cash and margin balances from Interactive Brokers on a read-only token that cannot trade — drawn from the daily statement, consolidated across every account, with borrowings shown against the holdings they finance.
The operating stake, the apartment, the private credit note, the cold-storage wallet — each carried at a documented basis, with mortgage balance, rate, payment and maintenance recorded against the property.
Each document is versioned, linked to the record it proves — a filing, an entity, an asset — and searchable. Nothing is a loose file.
Portfolio and private assets folded into the structure that holds them, net of debt at each level — so ‘what sits under the Panama company’ has an answer that adds up.
Objectives with a date and a number, tracked against net worth as it moves, and large expected outflows recorded before they land — so a purchase and a filing deadline sit on the same horizon.
As the record fills in, Mithduin reads it and raises what is worth a conversation: an apartment held in a personal name where a corporation, foundation or trust may serve better; an entity with nothing in the vault to prove its standing; a filing marked complete with no filed copy attached; four jurisdictions on record and an empty travel log.
Findings are produced by deterministic rules over your own data — the system cannot invent one — and are written as questions for your advisers, never as instructions. Each note carries a secure Ask about this button that reaches your advisory team with the context already attached.
This is the most sensitive record a person keeps, and it is treated that way. What follows is what the system does today — not an aspiration.
Every table carries row-level security. A signed-in client can read and write only the rows belonging to their own workspace, and that boundary is enforced by Postgres itself — not by application code that a bug could bypass.
TLS on every connection; AES-256 at rest. Documents live in a private bucket with no public URLs and are opened only through signed links that expire after five minutes.
The Interactive Brokers connection uses a Flex Web Service token, which retrieves statements and positions. It cannot place a trade or move funds, and can be scoped to a single IP and revoked at any time.
Your record is never sold or shared. When you ask for suggestions, a structured summary of the relevant fields — never your documents — is sent to a model provider under commercial terms that prohibit training on it.
Export or deletion of the whole record is available on request. Access is by invitation, and every adviser who opens your file is recorded against it.
In progress: two-factor sign-in and passkeys. Both are on the near-term roadmap and are not claimed as live.
Mithduin is built and run by its founder, working with trusted advisors with expertise in international tax law (IRS, CRA, HMRC and EU regimes), structuring, trust and estate planning, asset protection and finance. The software keeps the record exact; the people judge what it means.
Mithduin is offered by invitation to a limited number of entrepreneurs. A private walkthrough of the record can be arranged on request.