Assumption Surfaces Register
Invisible expectations that persist until something goes wrong.
When someone holds Bitcoin, a set of assumptions quietly activate. These assumptions are rarely stated, rarely tested, and not assigned to anyone. They persist until a stress event — death, device failure, incapacity, dispute — reveals that the expectation was never verified.
This register names those assumptions. It does not judge whether any assumption is right or wrong. It documents what people expect but do not confirm.
Assumption surfaces are not failures. They are expectations that have not been assigned, checked, or written down.
What an Assumption Surface Is
An assumption surface is something people expect to be true about their custody setup without having verified it. It is different from a scope boundary — which shows where a professional's job ends. An assumption surface shows where an expectation exists that no one has formally accepted responsibility for.
These assumptions are structural. They are not mistakes. They exist because Bitcoin custody works differently from every other asset people own. Banks, brokerages, and institutions handle most of these expectations automatically for traditional assets. With Bitcoin, no one does.
Assumption Surfaces Activated by Bitcoin Custody
Backup Integrity Assumption
Assumption type: Operational
The expectation that backups work. That a seed phrase is readable, that a backup device functions, that a passphrase is recorded correctly, that stored materials have not degraded. Most people create a backup once and assume it remains valid indefinitely.
Activated when: someone needs to restore a wallet and discovers the backup is incomplete, corrupted, or inaccessible.
Heir Competence Assumption
Assumption type: Succession
The expectation that the person who inherits or receives custody instructions can actually follow them. That a spouse, child, executor, or trustee has the technical ability to use a hardware wallet, enter a passphrase, coordinate a multisig transaction, or verify a recovery process.
Activated when: the holder dies or becomes incapacitated and the designated person cannot complete the steps.
Professional Understanding Assumption
Assumption type: Competence
The expectation that the professionals involved — estate attorney, financial advisor, CPA, trustee — understand how Bitcoin custody works. Most professionals in these fields have not been trained in seed phrases, multisig coordination, hardware wallets, or key management.
Activated when: an attorney drafts a trust that references "Bitcoin accounts" without addressing cryptographic access, or an advisor reviews a portfolio without evaluating custody survivability.
See Attorney Bitcoin Training, Advisor Custody Risk Assessment
Instruction Completeness Assumption
Assumption type: Operational
The expectation that written instructions are complete enough for someone else to follow. That the steps include every device, every passphrase, every PIN, every location, every software version, and every coordination requirement. Most instruction sets have gaps the author does not notice because they fill them from memory.
Activated when: a family member follows the instructions exactly and gets stuck at a step the holder considered obvious.
Setup Persistence Assumption
Assumption type: Temporal
The expectation that a custody setup stays valid over time without maintenance. Custody arrangements degrade silently as devices age, firmware becomes outdated, people move, relationships change, cosigners become unreachable, and memory fades. A setup that works today may not work in three years.
Activated when: a holder tries to access Bitcoin after several years and discovers a device no longer functions or a cosigner is unreachable.
Coordinator Availability Assumption
Assumption type: Coordination
The expectation that all people required to complete a transaction — cosigners, keyholders, trusted contacts — will be available, willing, and capable when needed. Multisig and shared custody setups assume coordination. Stress events — death, dispute, incapacity, geographic separation — disrupt coordination.
Activated when: a multisig transaction requires three signatures and one keyholder has died, one has moved abroad, and one has lost their device.
Single-Point Awareness Assumption
Assumption type: Knowledge
The expectation that someone other than the holder knows the custody setup exists and where to find the information needed to access it. Many holders have not told anyone what they hold, where it is stored, or how to reach it. The information exists only in one person's head.
Activated when: a holder dies and no one in the family knows Bitcoin exists, or knows it exists but cannot find the access materials.
Product Coverage Assumption
Assumption type: Operational / Custody
The expectation that the custody product — hardware wallet, exchange, multisig service — handles inheritance, incapacity, disputes, and long-term access. Most products are designed to secure access for the current holder. They are not designed to transfer access under stress.
Activated when: a family discovers that the hardware wallet provider offers no inheritance support and the exchange requires a probate process that takes months.
See After Moving to Cold Storage, Exchange Bankruptcy Inheritance
Composure Transfer Assumption
Assumption type: Human
The expectation that the person executing a custody recovery will be calm, focused, and unhurried. Custody setups are designed and tested under normal conditions. Actual execution often happens under grief, time pressure, legal deadlines, family conflict, or cognitive decline. The gap between setup conditions and execution conditions is rarely accounted for.
Activated when: a grieving spouse attempts a multi-step recovery process for the first time, under estate deadline pressure, with no prior experience.
Why Assumptions Pass Between People Without Being Checked
Each person in your life — your attorney, your advisor, your spouse, your cosigner — handles their own part. But assumptions are not anyone's job. When Bitcoin enters the picture, expectations pass from one person to the next without anyone confirming them. Not because anyone is careless. Because no system exists to catch them.
This register documents where that commonly happens. The Professional Scope Boundary Matrix documents who assumes coverage exists. This register documents what is assumed.
When Assumptions Become Visible
These assumptions usually stay hidden during normal life. They become visible when something happens: a death, a device failure, a divorce, a medical emergency, an estate proceeding, or a tax audit. The assumption was always there. The event is what exposes it.
This register documents observed assumption surfaces. It does not judge any assumption or provide advice.
Version 1.0 — Published February 2026. Assumption surfaces may change as custody practices evolve.
For anyone who holds Bitcoin — on an exchange, in a wallet, through a service, or in self-custody — and wants to know what happens to it if something happens to them.
Start Bitcoin Custody Stress Test$179 · 12-month access · Unlimited assessments
A structured, scenario-based diagnostic that produces reference documents for your spouse, executor, or attorney — no accounts connected, no keys shared.
Sample what the assessment produces