Trust
Saying the same thing on both sides of the table.
Trust in this business is not warmth. It is the absence of a second version. What we tell an investor about a regulatory risk is what we have already told the sponsor, and what appears in a submission to an authority is what we would put in a diligence pack. Anything else survives only until the two parties speak to each other directly, which they eventually do.
That has a cost, and the cost is the point. It means telling a client a project is not viable when our fee depends on it proceeding. It means telling a sponsor that the partner they favour will not survive diligence. Advice that only pays when a transaction happens is not advice, and engagements are structured so that our judgement is not for sale with the work.
It also means the firm carries the consequences of being wrong rather than distributing them. Where we have misjudged a timeline or misread a requirement, the client hears it from us first, in writing, with what it changes.

