The insider threat on a trading desk

Every external control assumes the danger is outside. The insider threat inverts that assumption: the person with the access is meant to have it. On a trading desk this is uniquely sharp, because the people closest to the money are also the ones trusted to move it fast. Insider risk is not only the rare malicious actor, it is far more often the well-meaning employee who cuts a corner, and the design challenge is to contain both without paralysing the desk.

§01Least privilege, continuously

The foundation is that access should map to current need, not accumulated history. People change roles, cover for colleagues, and pick up permissions that are never revoked, the slow accretion that leaves a junior trader holding administrative rights nobody remembers granting. Periodic access reviews, scoped roles, and isolation between books keep the blast radius of any one person’s credentials small. The question is never "do we trust them" but "what would this credential do if it were used wrongly".

§02Separation of duties

The single most effective structural control is ensuring that no one person can complete a sensitive, irreversible action alone. The individual who can initiate a large withdrawal should not also be the one who approves it; the person who writes a strategy change should not be the sole party who deploys it to production. Separation of duties turns a unilateral act into a conspiracy of two, which is a dramatically higher bar, and it protects the honest majority as much as it deters the rare bad actor.

§03Attribution and the honest record

Insiders are constrained by the knowledge that actions are attributable. Every order, configuration change, and data export should tie to an individual through a tamper-evident audit trail that the individual cannot themselves alter. This is not surveillance for its own sake; it is the record that protects the innocent when something goes wrong and makes the guilty path unattractive. A desk where everything is attributable is a desk where mistakes get corrected instead of hidden.

§04A culture, not a cage

The aim is not to treat colleagues as suspects but to build a system where trust is backed by structure, least privilege, separated duties, and honest records, so that a single person’s error or malice is contained by design. This advisory is educational and illustrative and is not security, legal, or HR advice for any specific organisation.