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London Lock-in


In one of his latest comments, Paul Krugman mused about the Brexit contribution to the recent decline of the British pound. “Coming at it from the trade side” he first drew attention to what in economic research is called the home market effect. This is a phenomenon which helps explain why industries concentrate in large markets and exports occur:

A trade scenario

“Imagine a good or service subject to large economies of scale in production, sufficient that if it’s consumed in two countries, you want to produce it in only one, and export to the other, even if there are costs of shipping it. Where will this production be located? Other things equal, you would choose the larger market, so as to minimize total shipping costs. Other things may not, of course, be equal, but this market-size effect [my emphasis] will always be a factor, depending on how high those shipping costs are.”

Krugman then argued that the smaller market may not come away completely empty-handed. It may prosper by enhancing its price competitiveness:

“In one of the models I laid out in that old paper, the way this worked out was not that all production left the smaller economy, but rather that the smaller economy paid lower wages and therefore made up in competitiveness what it lacked in market access. In effect, it used a weaker currency to make up for its smaller market.”

For Krugman, the initial situation in Europe can be characterized by this example. The two countries in question are Britain as the smaller market and the rest of Europe as the larger one.

Now, with Brexit looming on the horizon, many observers are expecting a decline of the pound as a consequence of a resulting overall economic recession in Britain. But Krugman argued that a Brexit recession does not, so far, seem to be materializing. He offered an alternative explanation for the pound weakness focusing (1) on financial services as the industry in question and (2) a partial reversal of this industry’s location decisions as a key influence behind the currency decline:

“Now we face the prospect of seriously increased transaction costs between Britain and the rest of Europe, which creates an incentive to move those services away from the smaller economy (Britain) and into the larger (Europe).”

The question is: Is this a realistic scenario?

First of all, the focus on financial services in this context is a problem. Given the role the City plays for the British economy this seems to make sense at first glance. A closer look at the determinants of the competitiveness of this industry and related Brexit effects, however, calls for a different view. Neither is Europe – with or without Britain – in this context the relevant market, nor is the British pound necessarily the relevant currency.

The City of London is part of an international network of financial centres offering 24/7 services and trade in a wide variety of financial instruments. It is the world’s largest foreign exchange market – which is largely a wholesale market – with the British pound ranging behind US dollar, euro and Japanese yen. London’s main competitors are New York and Chicago as well as places in Asia such as Tokyo, Singapore and Hong Kong. Similar to New York in the United States and Tokyo in Asia London has a home advantage in Europe, but its role as a major world financial centre is not defined by its position there. Regional competitors such as Frankfurt and Paris have high hopes that Brexit will lastingly shake its status, but – beside the need to do without the European passport which inevitably will make SOME banks and other financial services companies choose to move SOME UK-based activities to the EU (Ben Martin) – most of this must be considered wishful thinking.

The competitiveness of the City as a location for international financial institutions is only marginally influenced by relative costs and prices in Britain and Europe. For their concentration in London other explanations must be found.

Edge-city complexity

In the 1990s, in a little book on The Self-Organizing Economy, Paul Krugman himself laid the theoretical foundations for a more adequate description of market concentration and clustering which might well apply to the financial industry, too.

In the book Krugman chose an interdisciplinary approach which stressed the importance of concepts such as complexity and emergence, the science about “how large interacting ensembles – where the units may be water molecules, neurons, magnetic dipoles, or consumers – exhibit collective behaviour that is very different from anything you might have expected from simply scaling up the behaviour of the individual units.” His edge city model presents a most rudimentary form of spatial concentration under complexity in which locational decisions are determined by two kinds of “forces”, a centrifugal and a centripetal one:

In the model, the decision of each firm where to locate depends on all other firms´ choices. On the one hand, firms are assumed to dislike having other businesses nearby because they compete for customers and resources. These are the centrifugal forces. On the other hand, to have other businesses close has advantages. For example, they attract customers to the place or add to the variety of local services offered. Krugman calls these considerations centripetal forces. Both together determine the extent to which businesses locate in “clumps”.

For the details of this approach the reader is referred to the original source.

History shows that there is a considerable element of persistence and inertia in the rise and decline of financial centres. From Amsterdam in the 17th century over London in the second half of the18th century and New York after World War I, and again in the postwar years, it took always great upheavals for a centre to lose its dominance (Paul Einzig).

Many observers think that Brexit is comparable to those upheavals. But, from Krugman we learn that no development – not even the most dramatic one – is influencing the rise or fall of markets single-handedly. The big merit of the little book is that, although not dealing explicitly with the financial industry, it is drawing attention to the complexity of the processes involved.

At this point, it is worth making a little effort and having a closer look at the evolutionary nature of spatial concentration in finance and economics. Here, even Krugman merely scratches the surface. Interpreting the City as a huge living financial organism, theories of complexity and evolution become a rich source of analogies which may help explain why Brexit is not the end of London’s supremacy.

This will come at some length, as not many people in economics are familiar with the concepts and may appreciate hints at ideas and basic references. The following draws heavily on several older discussion papers and publications of mine, which are not available online, but some of which may be found in the list here.

Emerging financial systems

As Krugman wrote, quoting Philip Anderson, the Nobel laureate physicist: Complexity is the science of “emergence”.

Emergence refers to a quality added to a system which is not inherent in its parts. For example, for Stuart Kauffman “life” is an emergent whole of biological systems which is not located in the property of any single molecule.

Considering complex financial markets as emergent systems has two aspects. One is, as already mentioned, spatial self-organisation. Under certain circumstances the interactions of many people taken together – of individuals, firms and financial institutions as well as the administrative and political environment – are able to create a new quality or “culture” of a market place allowing it to become a truly international centre. Then, in principle, what needs to be explained is that process as well as the emergent quality.

The second aspect is path dependence. Broadly stated, path dependence means that a system’s current state is a function of past initial conditions and developments. This stands in contrast to traditional equilibrium models in economics which take as given that their results are generally valid, holding independently of what happened earlier. The term is closely related to another one which is lock-in: A system which has once reached a particular state may at times stay there even if this does not appear an optimum to outside observers. Path dependence and look-in are strong arguments for a financial centre to maintain a once-reached dominant position even if – whether for Brexit or other reasons – its competitiveness is in decline. On the other hand, it may also condemn a lagging place to stay behind forever.

Emergence refers to the “organic” change in nature by which a financial place becomes an international centre. Banks which decide to all establish their business in the same location do not constitute a centre in this sense. There are many markets and places in the world fulfilling functions and offering services that can be found in London, Tokyo  or New York as well. And many of the banks in London, Tokyo and New York have businesses elsewhere which are, in principle, engaged in the same kinds of activities.

What can be thought to make the difference is that with the growth of a market and increasing complexity sometimes – to draw another analogy to the natural sciences – a kind of self-organized criticality (as I wrote elsewere, this term which was coined by Per Bak originally described a type of macroscopic instability in
condensed-matter physics) is reached after which the place is not the same as before. Slowly and perhaps imperceptibly an adaption process to the needs and demands of internationally active participants in the market sets in meeting more and more criteria of a true international centre. Respective facilities grow, and norms, rules of conduct, attitudes and behaviour patterns become established.


Nowadays, in economics there is a wide variety of evolutionary theories searching explanations for all kinds of social and economic change. Most of them share several characteristics which constitute a kind of common basis on which the following considerations are founded, too. (Compare also, for example, the very interesting article by Giovanni Dosi on Opportunities, Incentives and the Collective Patterns of Technological Change, in The Economic Journal 1997.)

For example, there is an emphasis of dynamics. None of those concepts is interested in simply explaining something being but is asking how it became what it is. Theories are explicitly microfounded. There is no “macrobehaviour” without “micromotives” (to quote the title of a much-noticed book by Nobel-prize winner Thomas Schelling which is also included in Paul Krugman’s references). Further, in a very broad sense, rationality is “bounded”. Agents are assumed to have at best an imperfect understanding of their environment.

In general, evolutionary theories stress the importance of three factors for evolution to take place: Mutation, natural selection and chance.

Mutation provides the material, i.e. the genetic difference, on which natural selection acts. As one famous geneticist put it: Mutation proposes but selection decides (Cavalli-Sforza and Cavalli-Sforza).

Natural selection enables a system or an organism to adapt to its environment driving it toward fitness maximisation and reproductive success.

Chance comes in in several ways. On the one hand, there is a statististical effect known as genetic drift. The carrier of a mutation may die without passing the mutation on to subsequent generations. Or, in contrast, the mutation may be spreading widely due to casual events. On the other hand, mutation itself occurs randomly. Chance makes evolution not just the survival of the fittest but also the survival of the luckiest.

And there is more: For evolution to take place by natural selection there must be replicators and interactors. A replicator passes on its structure intact in successive replications. Genes are replicators. Interactors are by their very name entities that “interact as a cohesive whole with their environment in such a way that this interaction causes replication to be differential.” (Alexander Rosenberg in Philip Mirowsky) In biology, this can be organisms, but also cells, genes, tissues, organs and the like.

Another useful term in evolutionary theories is lineage standing for the entity which actually evolves. In general, lineage is defined as the line of decent which can be traced from a common ancestor.

Interactors are composed of lines of descent and some proportion of types of interactors in the system or organism is changing from generation to generation.

In order to demonstrate the meaning of the different terms, the analogy can be tried on an example from economics. A firm which is switching to more adapted rountines is developing, growing in size and increasing its profitability. But, for evolution to take place at the firm level, it must become its own descendant, otherwise the analogy breaks down. According to evolutionary theory, changes within one member of the lineage do not count as evolution. They are simply a matter of development. The improved adaption has to be passed on to descendants, successors, subsidiaries or the like.

Reaching beyond Krugman’s edge city approach of centripetal and centrifugal forces, an analysis of an evolutionary economic system has to find an answer to the following questions:

What is it that is evolving and what is the lineage?

What are the generations?

Which are the replicators and interactors and

how can “fitness” be measured in this context?

Financial centre evolution

With respect to international finance, the answers to some of these questions have been suggested earlier. The evolving entity may be an international financial centre. Interactors there are individuals and firms but also markets and market segments as well as institutions and other entities developing the “rules of the game” in the market place. Those rules may consist of laws and regulations but may include norms, conventions and behavior patterns passed on from generation to generation of actors as well.

In this framework, the replicators which pass on their structures intact in successive replications may be thought of, not as the banks and financial institutions and other actors themselves, but as the inherited characteristics, laws, rules of conduct and long-term behavior patterns those actors develop over time, and over generations, which eventually make up for the market “culture”. What is reproduced again and again, constantly adapting to the environment, are the interacting components of this culture which allow the place to survive and thrive.

Each financial centre is distinct from any other market place in the world. With respect to its competitiveness one could think of several measures of “fitness”. One might be a place’s share, regional or worldwide, in particular market segments such as stocks or derivatives. Another could be the range of financial instruments available or the number and size of foreign institutions located there.


One aspect deserving special attention in this context is the phenomenon of lock-in. For the spatial organisation of financial centres this point is of special importance. Although financial services are considered widely as “footloose industries” which are not restricted in their choice of location, once established they shun changing places which then becomes costly and cumbersome. One reason for this inflexibility is found in their size and range of activities, which has at least three aspects: Reliance on producers services, dependence on the built environment and the need for face-to-face contacts.

Financial institutions depend on a vast net of suppliers of so-called producer services. Those include advertising, accounting, management consulting, legal services, (pizza services …) and many more. Central to the rise of those services was the growing size, complexity and diversification of the firms. They have a vast diversity of separate functions, and often geographical dispersal, with the result that banks’ central headquarters are no longer simply centres for administration and control but function as centres for orientation of the firm within its business environment. They decide about overall policies concerning clients’ business, trading strategies, risk management and the like but also about product development and expansion as well as mergers and acquisitions in a multiplicity of situations and countries. In this environment, providing certain highly specialised services in-house is costly and often no longer possible (Saskia Sassen).

Reliance on producer services is one argument against the financial industry’s footloose nature. Another is an increasing dependence on the built environment. While in former times, developers used to put up offices for financial institutions, which, in principle, were able to move easily in and out, on a speculative basis, banks’ requirements now have become too specialized for this to work and major houses tend to design their own buildings. For example, financial institutions need large trading floors and, depending on a certain technology to handle the huge volume of transactions traded every day, they require adequate space for cables and outlets as well as a pool of technical personnel to operate and repair equipment (Susan Fainstein).

The third argument is the ongoing need for personal, face-to-face contacts in financial markets. The core of financial activities can still be described as “information, expertise, contacts” (Nigel Thrift). In general, all of these require spatial proximity although the advantages vary in their intensity from product to product. For small securities trades, interbank payments or standardised foreign exchange dealing they are probably minuscule. For mergers and acquisitions, the management of investors’ portfolios or the lead management of syndicates they are high.

Besides, there is still another argument for financial agglomeration in the big centres which is identification with a place in its broadest sense. In general, people living and working in world cities like New York, London and Tokyo are aware of their special status. They may complain about the disadvantages such as air pollution and traffic jams, but they also enjoy the advantages. Some of these are in part imaginary by nature, consisting of an experience of a certain way of life, the feeling to be part of a special culture, which differs from those elsewhere.

In particular the financial community located in those cities has become an entirely distinct class breeding its own rules, norms, rituals and behaviour patterns. Financial places in this sense are not only places of financial intermediation but interactional proving grounds, centres of representation (of “where the stories are”) as well as centres of discursive authority (Nigel Thrift). They are places where individuals are bound together by a common “market  culture”, differing from centre to centre, which is not easily given up in exchange for another environment.


Krugman and other authors taught us, that, in general, there is no one-dimensional explanation for the concentration of industries. Relative costs and prices may influence the choice of a location, but they are only one element in a complex environment of reactions and interactions. The same holds for instutional and political changes. Brexit may be a good reason to reconsider the choice to locate in London, but countless lock-in effects in their sum may offer a stronger argument against moving.

But let us come back to Krugman’s initial question.

What about the pound?

In my view, last months’ weakness of the British currency is rather the result of short-term reactions of the foreign exchange market on various time scales in an environment of large and growing uncertainty, with self-reinforcing elements such as market technicalities and automatic rules. In this environment, policy and business actions are watched nervously, and statements and media reports which otherwise would go widely unnoticed have the quality to shake market fundaments. In addition, as Alex Krüger (@Trading_Macro) reminded us on Twitter no reasons are needed at all for market unrest and even the emergence of new trends these days:

The pound can be expected to remain volatile amid Brexit uncertainties and may even reach new extremes. The flash crash of October 7 gave an idea of the extent of the danger. To quote @zerohedge:

“At just after 7 minutes after hour, whether 7pm on the east coast, midnight GMT or early Friday morning in Asian trading, pound sterling plunged by more than 6%, in the span of 2 minutes although the bulk of the plunge took place in just 30 seconds: from 7:16 to 7:46, when the market became “disorderly” in technical parlance, or in simple terms, broke.”

Note also the international dimension: The main currency pair affected was not the euro/pound as some observers speculated but the US dollar vis à vis other major currencies – pound, euro and Japanese yen. Once again it became apparent that the foreign exchange market knows no boundaries. Limiting currency contagion worldwide will be one of the Brexit challenges ahead.


From → Markets

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