What Happens to Your Bitcoin When You Die

Chainalysis estimates 2.3 to 3.7 million Bitcoin sit permanently lost. That's 11 to 18 percent of every coin ever mined. The methodology flags coins that haven't moved in five years and strips out known long-term holders. The conclusion holds either way: a large slice of the supply is gone.

Nobody knows how much of that pile belonged to people who died. Anyone who quotes you a precise figure invented it. Inheritance lawyers who handle digital assets see the same pattern though. Early holders who accumulated between 2009 and 2013 died without leaving instructions. The family inherited the house, the car, the bank accounts. The hardware wallet sat in a drawer next to old phone chargers. Nobody recognised it. Eventually it became inaccessible. You cannot recover it. You cannot inherit it. It is gone.

Every Bitcoin holder I know worries about inheritance. Almost none of them have written anything down. This chapter is here to change that for you.

Legal Rights Don't Unlock Wallets

A bank account has a custodian. So does a brokerage account, a pension fund, a life insurance policy. When you die, your heirs hand the institution a death certificate and a certificate of inheritance, and the institution cooperates because it must.

Bitcoin in self-custody works differently. The Bitcoin network has no customer service number. It has no forgot-password form. No probate court can compel a blockchain to release funds. The network does not know who you are. It does not know you are dead. It responds only to the correct cryptographic key.

If your heirs lack the seed phrase, the 12 or 24 words that reconstruct your private keys in any compatible wallet, they cannot access your Bitcoin. Your will does not matter. A Swiss court order does not matter. The coins sit there, visible on the blockchain, mathematically locked, forever.

This is the gap that makes Bitcoin different from every other estate asset. The legal right to inherit something and the technical ability to access it are two separate problems. Your children may hold an enforceable claim to your Bitcoin under Swiss law and still never touch a satoshi of it.

What Swiss Law Actually Says

Articles 457 to 640 of the Swiss Civil Code pull every asset you owned into the estate, the Nachlass. Bitcoin counts. It is a Vermögenswert, an asset with value, and it joins your estate whether or not your will mentions it.

The forced heirship rules, the Pflichtteil, protect your children from full disinheritance. The 2023 reform set their protected minimum at half of their intestate share. If Bitcoin makes up real value in your estate, your children hold a legal claim to a proportional cut. A will that hands everything to a partner or a foundation will fold when the children invoke their Pflichtteil.

Then the law collides with self-custody. A Swiss court can rule that your children are entitled to a specific share of your Bitcoin. It can issue orders. It can appoint estate executors. None of it matters without the seed phrase. Swiss inheritance law is mature and well-tested. It just was not built for cryptographically locked assets. The law assumes property can be physically transferred or pried out of a custodian. A self-custodied wallet has no custodian, and a court order cannot move coins.

Bitcoin held at a regulated Swiss exchange is different. Bitcoin Suisse, Swissquote, and their peers act as the custodian. Your heirs hand over a Sterbeurkunde and an Erbenbescheinigung from a Swiss notary or court, and the exchange runs the standard estate process. It takes paperwork and patience, but it works. The exchange holds your Bitcoin on your behalf, and on your death it transfers custody to verified heirs, the same way a bank does.

Self-custodied Bitcoin, whether on a hardware wallet or a paper backup or anything in between, has no such mechanism. The exchange is not involved. The notary is not involved. The blockchain is indifferent.

The Four Ways Bitcoin Inheritance Fails

Read the failure modes first. They tell you exactly what to defend against.

Mode 1: Heirs don't know Bitcoin exists. Most common failure. The holder never mentioned it. No bank statement points to it. The family liquidates the obvious assets, sees a strange USB stick in the desk drawer, and throws it out with the chargers. The Bitcoin vanishes and nobody understands what was lost.

Mode 2: Heirs know Bitcoin exists but can't access it. The family knows there were coins. Maybe the deceased mentioned them at a dinner. Maybe an old exchange email survives in the inbox. But no seed phrase turned up. The hardware wallet asks for a PIN nobody knows. After a handful of wrong attempts, the device wipes itself. Knowing Bitcoin exists is one problem. Reaching it is another.

Mode 3: Hardware wallet found, seed phrase found, passphrase undocumented. The cruellest scenario. Your heir follows the trail. They find the hardware wallet. They find the 24-word seed. They run the recovery and watch the wallet open with a zero balance. They assume the coins were already spent and give up. What actually happened: you set a BIP-39 passphrase, sometimes called the 25th word, which spins up a hidden wallet behind the same seed. The seed alone unlocks a decoy. Your real funds sit behind the passphrase you never wrote down. The Bitcoin is still there, fully intact, untouchable.

Mode 4: Exchange account found, 2FA on a dead phone. Your heir digs up the username and password. The account asks for the six-digit code from an authenticator app on the deceased's phone, now locked or wiped, or from an SMS to a number the carrier already recycled. Without the 2FA backup codes, the exchange's manual recovery process eats weeks of legal documentation. Most people never save those backup codes anywhere their family will find them.

Every one of these failures is preventable. All four ask for the same thing: a person, before they died, wrote something down and stored it somewhere their family could reach.

Five Solutions, From Simple to Sophisticated

The Inheritance Letter

Write a letter. Not a legal document. Not a technical manual. A plain letter that tells your heirs what they need to know.

In Switzerland, a signed letter sealed in an envelope and deposited with your notary or your Erbrechtsanwalt is a recognised supplement to a will. It does not replace the will, but it carries the practical access instructions a will never contains. A handwritten will, a holographisches Testament, is legally valid if it is fully handwritten, signed, and dated. An inheritance letter can sit alongside it.

The letter should cover:

• A clear statement that you hold Bitcoin and where it lives, both exchanges and self-custody wallets
• The brand and model of any hardware wallet, and where the physical device sits
• The location of the seed phrase. Reference where it is stored, not the words themselves, if the letter shares a location with the seed
• Whether you set a BIP-39 passphrase, the 25th word, and where to find it. This is where most heirs lose the coins
• The hardware wallet PIN
• Exchange account names, the registration email, and the username
• Where the 2FA backup codes live, or which device holds the authenticator app
• A contact, with phone number, who is technically capable of guiding your heir through the recovery
• The date you wrote the letter, so your heirs know how fresh the instructions are

Skip the seed phrase itself if the letter sits anywhere unsecured. If the letter goes into a sealed envelope at your notary, you can include everything together. If the letter might be found earlier by the wrong person, keep the seed somewhere else and point to it.

The letter costs nothing. It takes an hour. For most Bitcoin holders it is the single most effective move you can make today.

Shamir's Secret Sharing

If you want structural protection against both loss and theft, Shamir's Secret Sharing, shipped in hardware wallets as SLIP-39, splits your seed into multiple shares.

A 3-of-5 setup splits the seed into five shares and any three reconstruct the original. You might place one in a bank safe deposit box, one with a family member, one with your lawyer, one in a fireproof home safe, one with a second trusted party. Any three of those five rebuild your wallet. No single person holds everything, which also cuts your theft risk while you are alive.

Trezor Safe 7, Safe 5, and Safe 3 support this. Most other devices do not, so the setup locks you to one hardware family. Heirs also have to understand that they need to coordinate with other share-holders before they can recover anything. For a holder with significant size and access to multiple trusted parties, it beats a single seed document on resilience.

Multi-Signature Inheritance

Multi-signature custody demands multiple independent keys to authorise any transaction. A 2-of-3 setup means three keys exist and any two together can spend. Done right, it removes the single point of failure that haunts every single-seed setup.

A practical inheritance structure: you hold one key on your hardware wallet, your Swiss notary or trusted lawyer holds the second in a sealed envelope, and the third sits in cold storage your heirs can reach. While you are alive, you sign with your key and the cold storage key. The lawyer's key never moves. After you die, your heirs collect the cold storage key, pair it with the lawyer's, and have the two signatures they need to spend.

Two services build inheritance directly into managed multisig. Casa runs two managed-multisig tiers: a Standard 2-of-3 vault at USD 250 per year and a Premium 3-of-5 vault at USD 2,100 per year, and both include inheritance. Confirm the latest numbers at casa.io/pricing before you subscribe. Unchained Capital runs a collaborative-custody model with an explicit inheritance protocol designed so heirs can recover Bitcoin without learning the technical mechanics themselves. Both companies are US-based. Swiss residents can use them because the custody itself is non-custodial and works globally, but their estate-attorney integrations target the US legal system. If you are in Switzerland, pair the service with a Swiss notary or Erbrechtsanwalt so the legal documentation lines up with Swiss inheritance law.

Digital Inheritance Services

Vault12 is a non-custodial mobile app that lets you assign a guardian who holds an encrypted fragment of your wallet backup. The company never touches your keys. The guardian, who might be a family member, lawyer, or trusted friend, holds the encrypted share and triggers the recovery process for your heirs when you die. Vault12 ships globally through the Apple App Store and Google Play (vault12.com). Swiss residents install it on the same terms as everyone else, and the service is not a Swiss-regulated financial institution.

Sarcophagus is a decentralised protocol on the BASE blockchain that runs as a dead man's switch. You encrypt a file, perhaps a seed phrase or a set of access instructions, and set a resurrection timer. Check in before the timer runs out and it resets. Miss the check-in and the encrypted file releases to a designated recipient. If you die or become incapacitated, your heir eventually receives the file automatically. The protocol runs on smart contracts, which brings its own risks: protocol bugs, token-economics uncertainty, and the requirement that your heir knows to look for the message and how to decrypt it.

Both services are newer than the legal instruments. Treat them as an additional layer in a broader plan, not a standalone solution.

Exchange Custody for Smaller Amounts

Bitcoin held at a regulated Swiss exchange is the simplest inheritance scenario. Your heirs walk through the standard estate process: death certificate, Erbenbescheinigung from a notary or court, contact the exchange's estate team. The exchange cooperates. It takes time. It works.

The trade-off is counterparty risk while you are alive. You do not hold the keys. The exchange could be hacked, become insolvent, or freeze withdrawals for regulatory reasons. I am not arguing exchange custody is wrong. It is a deliberate choice, with conditions self-custody avoids.

For smaller holdings, or as a deliberate slice of your inheritance plan, exchange custody is reasonable. For everything you intend to hold long-term in self-custody, the other solutions above apply.

How Much You Hold Shapes What You Do

The right approach tracks what you are protecting.

Under CHF 10,000: an inheritance letter combined with exchange custody for at least part of the position is proportionate. Write the letter, deposit it with your notary or store it sealed alongside your will, and document your exchange accounts clearly.

Between CHF 10,000 and CHF 100,000: the inheritance letter is your floor. Layer Shamir's Secret Sharing on a Trezor or a basic multisig setup on top, and you cut your exposure to both loss and theft meaningfully.

Above CHF 100,000: the professional multisig services, Casa or Unchained, with formal legal integration through a Swiss estate lawyer earn their keep. At this size, the annual cost of professional custody is rounding error against the value you are protecting, and the legal clarity around inheritance matters more.

These are frameworks. Not financial advice. Your family structure, the technical chops of your heirs, the number of wallets and exchange accounts you run will all shift the answer.

What to Do This Week

Write the letter.

Not next month. Not when you have time to research the perfect solution. This week, take an hour and write a clear document that tells your heirs what they need to know. Where is the Bitcoin? Where is the hardware wallet? Where is the seed phrase? Did you set a passphrase? What exchange accounts exist? Where are the 2FA backup codes?

A rough draft in a sealed envelope in your safe today beats a perfect plan you never wrote. The detailed solutions, Shamir shares, multisig custody, digital services, can follow. The letter goes first.

Date the letter. Review it once a year, or whenever something changes: a new wallet, a new exchange account, a hardware swap. You are not aiming for a perfect document. You are aiming for a document that exists.

If you have a notary in Switzerland who already handles your estate documents, ask about depositing a sealed envelope with the will or beside it. It is standard practice and costs almost nothing. Your heirs will never call a blockchain for your Bitcoin. They will look to what you left behind.

This chapter is general information, not legal advice. Swiss inheritance law turns on your specific circumstances, and anyone with significant Bitcoin holdings should consult an Erbrechtsanwalt familiar with digital assets.

Chapter Summary

• Chainalysis estimates 2.3 to 3.7 million Bitcoin sit permanently lost, and a real share belongs to holders who died without leaving access instructions. None of it comes back.

• Swiss law treats Bitcoin as an estate asset under the Civil Code. The Pflichtteil protects your children. Legal entitlement is worthless without the seed phrase, because no court order unlocks a self-custodied wallet.

• The four failure modes are preventable: heirs not knowing Bitcoin exists, knowing but lacking access, finding a seed that opens only a decoy because an undocumented passphrase guards the real wallet, and getting locked out of an exchange by 2FA on a dead phone.

• The inheritance letter, deposited with a notary, lawyer, or fireproof safe alongside your will, is the highest-leverage move most Bitcoin holders can make. Write it this week.

• Shamir's Secret Sharing (SLIP-39), multisig custody via Casa or Unchained, and digital services like Vault12 add resilience for larger holdings. The right stack depends on size and family structure.