Consulting firms sell expertise, and their currency is trust. Large consultancies like Boston Consulting Group, Bain, McKinsey, Deloitte, Accenture and others make their money from being a trusted advisor to companies around the world. Why do companies trust them?
One reason is that companies always value an external perspective, and there is a large army of alumni from these firms in organizations around the world guiding their leadership to choose their former employer as that external perspective or that extra pair of hands needed in tackling a large strategic challenge.
