Matt Elliott

Professor of Economics, Cambridge University

Fellow, Jesus College

European Research Council (ERC) Sponsored Research

Embedded Markets and the Economy (EMBED)

(Project ID: 757229)


Contact Information

Email: mle30 [at] cam.ac.uk

Room: 42

Address: Faculty of Economics, Austin Robinson Building, Sidgwick Avenue, Cambridge, CB3 9DD.

CV


Published and accepted papers

Investments in social ties, risk sharing and inequality (Supplementary Appendix) (with Attila Ambrus)

Review of Economic Studies, 2021


The importance of social norms against strategic effects: The case of COVID-19 vaccine take up (with Marina Agranov and Pietro Ortoleva)

Economic Letters, 2021


Systemic Risk-Shifting in Financial Networks (with Jonathon Hazell and Co-Pierre Georg)

Journal of Economic Theory, 2021


Commitment and (In)Efficiency: a Bargaining Experiment (Supplementary Appendix) (with Marina Agranov)

Journal of the European Economic Association, 2021


A Network Approach to Public Goods (Supplementary Appendix) (with Ben Golub)

Journal of Political Economy, 2019


Decentralized Bargaining in Matching Markets: Efficient Stationary Equilibria and the Core (with Francesco Nava)

Theoretical Economics, 2019


The role of Networks in Antitrust Investigations (with Andrea Galeotti)

Oxford Review of Economic Policy, 2019, Special issue on the economics of networks.


Networks and Economic Policy (with Sanjeev Goyal and Alex Teytelboym),

Oxford Review of Economic Policy, 2019, Special issue on the economics of networks.


Inefficiencies in Networked Markets (Supplementary Appendix)

American Economic Journal: Microeconomics, 2015.

Financial Networks and Contagion (with Ben Golub and Matt Jackson)

American Economic Review, 2014.


How Sharing Information Can Garble Experts' Advice (with Ben Golub and Andrei Kirilenko,)

American Economic Review: Papers and Proceedings, 2014.


Book Chapters and Review Articles

Investment in Matching Markets (with Eduard Talamas, Draft Date: May 2021)

To appear in: Online and Matching-Based Market Design. Editors: Federico Echenique, Nicole Immorlica and Vijay V. Vazirani. Cambridge University Press.


Networks and Economic Fragility (joint with Ben Golub )

Draft coming soon. Perpared for the Annual Review of Economics. Submitted: DOI


Working Papers

Supply Network Formation and Fragility (Supplementary Appendix)

Revision requested by the American Economic Review.

(with Ben Golub and Matt Leduc, Draft Date: February 2021)

We model the production of complex goods in a large supply network. Each firm sources several essential inputs through relationships with other firms. Individual supply relationships are at risk of idiosyncratic failure, which threatens to disrupt production. To protect against this, firms multisource inputs and strategically invest to make relationships stronger, trading off the cost of investment against the benefits of increased robustness. We find that equilibrium aggregate production is robust to idiosyncratic disruptions. Nevertheless, there is a regime in which arbitrarily small systemic shocks cause arbitrarily steep drops in output, so that the the supply network is fragile with respect to such shocks. The endogenous configuration of supply networks provides a new channel for the powerful amplification of shocks.


Market Segmentation through Information

Revision requested by the American Economic Review.

(with Andrea Galeotti and Andrew Koh, Draft Date: December 2020)

Prodigious amounts of data are being collected by internet companies about their users’ preferences. We consider the information design problem of how to share this information with traditional companies which, in turn, compete on price by offering personalised discounts to customers. We provide a necessary and sufficient condition under which the internet company is able to perfectly segment and monopolise all such markets. This condition is surprisingly mild, and suggests room for regulatory oversight.


Capability Accumulation and Conglomeratization in the Information Age (Supplementary Appendix)

(with Jun Chen and Andrew Koh, Draft date: March 2021)

The past twenty years have witnessed the emergence of internet conglomerates fueled by acquisitions. We provide a simple theoretical model to shed some light on this. Following a large literature in management (Wernerfelt, 1984) we endow firms with a set of scarce competencies which drive their competitiveness across markets. Firms can merge to combine their competencies, spin-off new firms by partitioning their competencies, or procure unassigned competencies. We study stable industry structures, in which there are no profitable mergers, demergers, or procurements, and find an upper and lower bound on the size of the largest firm. As markets increasingly value more of the same competencies, abrupt transitions in these bounds occur. We posit that this force can help explain the sudden conglomeratization of internet companies.


Bargaining foundations for price taking in matching markets

(with Eduard Talamas, Draft Date: February 2021)

In many markets, heterogenous agents make non-contractible investments before bargaining over both who matches with whom and the terms of trade. In static markets, the holdup problem—that is, inefficient investments caused by agents receiving only a fraction of their returns—is ubiquitous. Markets are often dynamic, however, with agents entering over time. Taking a general non-cooperative investment and bargaining approach, we show that the holdup problem vanishes in markets with dynamic entry as agents become patient: While there is substantial wiggle room for bargaining to determine outcomes, every bargaining outcome gives everyone her marginal product.


Work in progress

Network Bottlenecks and Market Power (joint with Vasco Carvalho and John Spray)

Draft coming soon.


Globalizing Supply Networks: The impact on Innovation and Fragility (joint with Matt Jackson)

Draft coming soon.


Older Work

Ranking Agendas for Negotiations (with Ben Golub, Draft date: February 2015)

Consider a negotiation in which agents will make costly concessions to benefit others -- e.g., by implementing tariff reductions, environmental regulations or nuclear disarmament. An agenda specifies which issue or dimension agents will make concessions on; after an agenda is chosen, the negotiation comes down to the magnitude of each agent's contribution. We seek a ranking of agendas based on the marginal costs and benefits they each generate at the status quo, which are captured in a Jacobian matrix. In a transferable utility (TU) setting, there is a simple ranking based on the best available social return per unit of cost (measured in the numeraire). When transfers are not available, the problem of ranking agendas is more difficult, and we take an axiomatic approach. First, we require the ranking not to depend on economically irrelevant changes of units. Second, we require that the ranking be consistent with the TU ranking on problems that are equivalent to TU problems in a suitable sense. The unique ranking satisfying these axioms is represented by the spectral radius (Frobenius root) of a matrix closely related to the Jacobian, whose entries measure the marginal benefits per unit marginal cost agents can confer on one another.


Heterogeneities and the Fragility of Labor Markets (Draft date: Nov 2015)

Workers' labor market participation decisions and firms' vacancy creation decisions are studied in a model where different matches generate different surpluses. An immediate consequence of these heterogeneities is that better matches are possible in thicker markets. This creates a thick market externality: when additional workers and firms enter the market, they confer net benefits on the other workers and firms by improving the expected quality of their matches. As a consequence, there is always too little entry by both workers and firms. The thick market externality has further implications. Quite generally labor markets will be fragile. Considering shocks to average match productivities, there will be a critical threshold at which a labor market suddenly collapses from supporting multiple workers and multiple firms in equilibrium to supporting no workers or firms in any equilibrium. All but one agent will suffer discontinuous losses as this threshold is passed and the market collapses.

COVID-19 related work

Which firms that are essential for ensuring the production of crucial goods and services in times of pandemics?

Vasco Carvalho, John Spray and I, take a supply chain network view on this and argue that business-to-business transaction data + economic theory can help locate "bottleneck" firms: firms which, directly or indirectly, ensure final production meets demand for key goods (e.g. vaccines) and services in the economy. We also offer a proof of concept based on such data. Out here. A short presentation on this can be viewed here.


Can robust supply chains be expected to form, and what are the implications for macroeconomy?

Ben Golub, Matt Leduc and I have a new paper showing that business' investments in their supply chain, like the extent of multisourcing they do, have a tendency to make supply chains fragile. Ben tweets about the paper and some of the implications for better understanding the impact of COVID-19 on the economy here.