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Crypto-currency Markets

Paper Session

Saturday, Jan. 5, 2019 8:00 AM - 10:00 AM

Atlanta Marriott Marquis, International 6-7
Hosted By: American Economic Association
  • Chair: Antoinette Schoar, Massachusetts Institute of Technology

Some Simple Bitcoin Economics

Harald Uhlig
,
University of Chicago
Linda Schilling
,
Ecole Polytechnique CREST

Abstract

In an endowment economy, we analyze coexistence and competition between traditional fiat money (Dollar) and cryptocurrency (Bitcoin). Agents can trade consumption goods in either currency or hold on to currency for speculative purposes. A central bank ensures a Dollar inflation target, while Bitcoin mining is decentralized via proof-of-work. We analyze Bitcoin price evolution and interaction between the Bitcoin price and monetary policy which targets the Dollar. We obtain a fundamental pricing equation, which in its simplest form implies that Bitcoin prices form a martingale. We derive conditions, under which Bitcoin speculation cannot happen, and the fundamental pricing equation must hold. We explicitly construct examples for equilibria.

Blockchains, coordination and forks

Bruno Biais
,
Toulouse School of Economics
Christophe Bisiere
,
Toulouse School of Economics
Matthieu Bouvard
,
McGill University, Desautels Faculty of Management
Catherine Casamatta
,
Toulouse School of Economics

Abstract

Blockchains are distributed ledgers, operated within peer-to-peer networks. If reliable and stable, they could offer a new, cost effective way to record transactions, but are they? We model the proof-of-work blockchain protocol as a stochastic game and analyse the equilibrium strategies of rational, strategic miners. Mining the longest chain is a Markov perfect equilibrium, without forking, in line with Nakamoto (2008). The blockchain protocol, however, is a coordination game, with multiple equilibria. There exist equilibria with forks, leading to orphaned blocks and persistent divergence between chains. We also show how forks can be generated by information delays and software upgrades. Last we identify negative externalities implying that equilibrium investment in computing capacity is excessive.

An Economic Analysis of the Bitcoin Payment System

Gur Huberman
,
Columbia University
Jacob Leshno
,
Columbia University
Ciamac Moallemi
,
Columbia University

Abstract

Abstract Although radically different from a traditional payment system, Bitcoin is functional and transmits value over the internet. Having fixed transaction processing capacity, it experiences service delays which motivate users to pay for service priority. These fees fund the computer servers (“miners”) which support Bitcoin. This paper models Bitcoin as a platform that intermediates between users and miners. It derives closed form formulas of the fees and waiting times and studies their properties; compares the economics of the Bitcoin payment system (BPS) to that of a traditional payment system operated by a profit maximizing firm; and suggests protocol design modification to enhance the platform’s efficiency. The appendix describes and explains the main attributes of Bitcoin and the underlying blockchain technology.

Trading and Arbitrage in Crypto-currency Markets

Igor Makarov
,
London School of Economics
Antoinette Schoar
,
Massachusetts Institute of Technology

Abstract

We study the efficiency, price formation and segmentation of cryptocurrency markets. We document large, recurrent arbitrage opportunities in cryptocurrency prices relative to fiat currencies across exchanges, which often persist for weeks. Price deviations are much larger across than within countries, and smaller between cryptocurrencies. Price deviations across countries co-move and open up in times of large appreciations of the Bitcoin. Countries that on average have a higher premium over the US Bitcoin price also see a bigger widening of arbitrage deviations in times of large appreciations of the Bitcoin. Finally, we decompose signed volume on each exchange into a common and an idiosyncratic component. We show that the common component explains up to 85% of Bitcoin returns and that the idiosyncratic components play an important role in explaining the size of the arbitrage spreads between exchanges.
Discussant(s)
Randall Wright
,
University of Wisconsin
Zhiguo He
,
University of Chicago
Leonid Kogan
,
Massachusetts Institute of Technology
Jonathan Berk
,
Stanford University
JEL Classifications
  • G1 - General Financial Markets