Access and continuity
The number of people whose sudden absence would stop something important — and in most small companies the answer for the digital estate is one.
Also called Bus factor · Единая точка отказа
It is rarely a deliberate decision. One person set up the hosting, so they hold it; they built the integration, so only they understand it; they know the client's real requirements, because those were agreed by phone. Each step is reasonable and the aggregate is a company whose website, mail and pipeline depend on a single individual's continued goodwill and availability.
The test is a question, asked out loud: if this person did not come back on Monday, what would we be unable to do? The answers are the risk register, and each one has a cheap fix — a second administrator, a written runbook, credentials in a shared vault, a repository the company controls.
The concentration is worst where it is least examined: the person who is trusted. Trust is a reason to give someone access; it is not a reason to give them exclusive access, and conflating the two is how well-run companies end up with no way to reach their own DNS.
Raising the subject is heard as suspicion, so it is not raised. But the common causes are not betrayal — they are illness, a visa that did not renew, a better offer, or an account recovery that failed. Frame it as continuity, document it once, and it stops being about any individual.
The definitions are the easy part. Whether the figure on your dashboard was computed this way is a different question, and usually the more expensive one.