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40 The number of relationships humans are felt able to maintain is believed to lie below 150 – so-called Dunbar’s Law. 41 For most of us, it is singledigits. That number has been roughly the same since the dawn of time, despite the extraordinary recent advance of technology and social networks. As Nicholas Christakis has observed, Facebook “friends” are not really your friends. With hindsight, this crisis has provided many examples of failures rooted in an exaggerated sense of knowledge and control. Risks and counterparty relationships outstripped banks’ ability to manage them. Servers outpaced synapses. Large banks grew to comprise several thousand distinct legal entities. When Lehman Brothers failed, it had almost one million open derivatives contracts – the financial equivalent of Facebook friends. Whatever the technology budget, it is questionable whether any man’s mind or memory could cope with such complexity. To sum up, the maximum efficient scale of banking could be relatively modest. Perhaps it lies below $ billion. Experience suggests there is at least a possibility of diseconomies of scale lying in wait beyond that point. Conglomerate banking, while good on paper, appears to be more mixed in practice. If these are not inconvenient truths, they are at least sobering conjectures. They also sit awkwardly with the current configuration of banking. In 2008, 145 banks globally had assets above $ billion, most of them universal banks combining multiple business activities. Together, these institutions account for 85% of the assets of the world’s top 1000 banks ranked by Tier 1 capital.