というNBER論文をルイジ・ジンガレスらが書いているungated版)。原題は「Political Determinants of Competition in the Mobile Telecommunication Industry」で、著者はMara Faccio(パデュー大)、Luigi Zingales(シカゴ大)。


We study how political factors shape competition in the mobile telecommunication sector. We show that the way a government designs the rules of the game has an impact on concentration, competition, and prices. Pro-competition regulation reduces prices, but does not hurt quality of services or investments. More democratic governments tend to design more competitive rules, while more politically connected operators are able to distort the rules in their favor, restricting competition. Government intervention has large redistributive effects: U.S. consumers would gain $65bn a year if U.S. mobile service prices were in line with German ones and $44bn if they were in line with Danish ones.



一昨日紹介したスティグリッツのNBER論文は大手銀行への彼への反発(cf. ここ)が滲んでいたが、この論文は、親企業よりは親市場を、というジンガレスの持論(cf. ここ)を反映しているようである。




というNBER論文をダグラス・ダイアモンドやラグラム・ラジャンらが書いているungated版)。原題は「Pledgeability, Industry Liquidity, and Financing Cycles」で、著者はDouglas W. Diamond、Yunzhi Hu、Raghuram G. Rajan(いずれもシカゴ大)。


Why are downturns following prolonged episodes of high valuations of firms so severe and long? Why do firms promise high external payments when they anticipate high valuations, and underperform subsequently? In this paper, we propose a theory of financing cycles where the control rights to enforce claims in an asset price boom (rights to sell assets) differ from the control rights used in more normal times (rights over cash flows that we term “pledgeability”). Firm management’s limited incentive to enhance pledgeability in an asset price boom can have long-drawn adverse effects in a downturn, which may not be resolved by renegotiation. This can also explain why involuntary asset turnover and asset misallocation to outsiders are high in a downturn as well as why industry productivity falls. The paper highlights an adverse consequence of high anticipated liquidity, working through leverage, on the economy’s access to finance and productivity when that liquidity fails to materialize.


企業価値の高評価が長く続いた後の景気後退はなぜ非常に深刻かつ長期なものとなるのだろうか? なぜ企業は、高評価を予期している時に外部への高額の支払いを約束し、その後業績が低迷するのだろうか? 本稿では、資産価格ブーム期における権利を行使するための支配権(資産売却権)が、通常期に使われる支配権(キャッシュフローに関する権利で、ここでは担保可能性と呼ぶ)と異なるという金融循環の理論を提示する。担保可能性を高める企業経営者インセンティブ資産価格ブーム期では限定的なものとなることが、再交渉では解消しないような景気後退期における長引く悪影響につながる可能性がある。これによって、外部への非自発的資産の引き渡しや資産の誤った割り当てが景気後退期で多くなること、および、業界の生産性が低下する理由も説明できる。本稿は、予期された高い流動性が、その流動性が実現しなかった時にレバレッジを通じて経済金融へのアクセスや生産性に与える悪影響を強調する。




というNBER論文スティグリッツ上げている原題は「Macro-economic Management in an Electronic Credit/Financial System」。


Modern technology provides the basis of an efficient low-cost electronic payments as an alternative to the current system where fiat money is the medium of exchange. This paper explores possible macro-economic implication, showing how such a financial system might enhance government’s ability to control the level of aggregate demand. As in other arenas, in second-best situations with uncertainty, systems where there is an attempt to directly control quantities directly may perform better (e.g. have less volatility) than those using prices and other indirect control mechanisms. The paper identifies conditions under which in a system of electronic money, macroeconomic variability is lower when the level and direction of credit creation is directly controlled, through appropriately designed credit auctions, than in a system of indirect control of, say, investment via the interest rate. This is especially important since much macro-economic instability is associated with instability in credit creation and in the fraction allocated to newly produced goods and services. The paper also explains how, in an open economy, in a system of electronic money, credit auctions combined with trade chits might enable the control of net exports, again enhancing macro-stability. Finally, we explain how under a system of electronic money, the rents that are currently associated with credit creation and that arise from bank franchises—that constitute a form of appropriation of the returns from trust in the government and its ability and willingness to bail-out banks in the event of a crisis or bank run—could be appropriated by the government to a greater degree than at present.






ジョシュ・ヘンドリクソン(Josh Hendrickson)のThe Everyday Economistブログエントリと、ノアピニオン氏のブルームバーグ論説が、ほぼ同時に恒常所得仮説を取り上げ、ほぼ正反対の評価を下している。


Mark Aguiar and Erik Hurst have a paper in the Journal of Political Economy that uses a cool data set that consists of food diaries of U.S. households. What the paper shows is that neither the quality nor quantity of food intake by retired households decline after retirement. In addition, they find that the food intake of unemployed workers does decline, but only as much as one would predict from the decline in permanent income typical of being displaced for some period of time from one’s job. In other words, if one considers the role of home production, then the evidence of a significant decline in expenditures following retirement or job displacement should not be interpreted as evidence against the permanent income hypothesis. Relying on expenditure data to measure consumption might cause one to incorrectly reject the permanent income hypothesis.




  1. 利用可能なミクロデータが増えるにつれ、仮説検定に乗り出す前に、研究対象となる変数を正しく計測しているかどうかを考慮することが重要になる。
  2. モデルをデータで検証する際に消費支出という標準的な尺度を使う場合には、モデルの家計の決定に自己生産も取り込んでおく必要がある。さもなければ、研究者の言う消費と計算された消費の間に不整合が生じる。


A new study by Peter Ganong and Pascal Noel shows that consumer behavior is more short term than almost any mainstream model predicts.


This means Friedman’s theory doesn’t just need a patch or two -- it needs a major overhaul.






We study the spending of unemployed individuals using anonymized data on 210,000 checking accounts that received a direct deposit of unemployment insurance (UI) benefits. The account holders are similar to a representative sample of U.S. UI recipients in terms of income, spending, assets, and age.

Unemployment causes a large but short-lived drop in income, generating a need for liquidity. At onset of unemployment, monthly spending drops by 6%, and work-related expenses explain one-quarter of the drop. Spending declines by less than 1% with each additional month of UI receipt. When UI benefits are exhausted, spending falls sharply by 11%.

Unemployment is a good setting to test alternative models of consumption because the change in income is large. We find that families do little self-insurance before or during unemployment, in the sense that spending is very sensitive to monthly income. We compare the spending data to three benchmark models; the drop in spending from UI onset through exhaustion fits the buffer stock model well, but spending falls much more than predicted by the permanent income model and much less than the hand-to-mouth model. We identify two failures of the buffer stock model relative to the data – it predicts higher assets at onset, and it predicts that spending will evolve smoothly around the largely predictable income drop at benefit exhaustion.





基礎固め基礎固め 2017/01/19 20:47 食料はみそですね…じゃなかた食料がみそですね





BOEのチーフエコノミストのアンドリュー・ホールデン(Andrew Haldane)が、OECD Insightsに「From economic crisis to crisis in economics」と題したブログエントリを上げ複雑系理論、就中、複雑な「システムのシステム」という観点から公的政策の全体構造を捉えることを唱えている*1ホールデンに言わせれば、経済金融のシステムを理解するのに複雑系理論はますます使われるようになっているが(例:大手銀行をスーパースプレッダーと見做した疫学モデル)、政策という観点からの複雑系理論の適用は未だし、とのことである。

Although there is no generally-accepted definition of complexity, that proposed by Herbert Simon in The Architecture of Complexity – “one made up of a large number of parts that interact in a non-simple way” – captures well its everyday essence. The whole behaves very differently than the sum of its parts. The properties of complex systems typically give rise to irregular, and often highly non-normal, statistical distributions for these systems over time. This manifests itself as much fatter tails than a normal distribution would suggest. In other words, system-wide interactions and feedbacks generate a much higher probability of catastrophic events than Gaussian distributions would imply.

For evolutionary reasons of survival of the fittest, Simon posited that “decomposable” networks were more resilient and hence more likely to proliferate. By decomposable networks, he meant organisational structures which could be partitioned such that the resilience of the system as a whole was not reliant on any one sub-element. This may be a reasonable long-run description of some real-world complex systems, but less suitable as a description of the evolution of socio-economic systems. The efficiency of many of today’s networks relies on their hyper-connectivity. There are, in the language of economics, significantly increasing returns to scale and scope in a network industry. Think of the benefits of global supply chains and global interbank networks for trade and financial risk-sharing. This provides a powerful secular incentive for non-decomposable socio-economic systems.

Moreover, if these hyper-connected networks do face systemic threat, they are often able to adapt in ways which avoid extinction. For example, the risk of social, economic or financial disorder will typically lead to an adaptation of policies to prevent systemic collapse. These adaptive policy responses may preserve otherwise-fragile socio-economic topologies. They may even further encourage the growth of connectivity and complexity of these networks. Policies to support “super-spreader” banks in a crisis for instance may encourage them to become larger and more complex. The combination of network economies and policy responses to failure means socio-economic systems may be less Darwinian, and hence decomposable, than natural and biological systems.






  1. 正確なデータと、システムの各層をタイミング良く把握することの重要性
    • 各層自体が複雑である場合には特に重要で、そうした複雑なサブシステム内およびサブシステム間の相互作用を捉えるためには、粒状データが必要となる。
  2. それら各層と層同士の相互作用のモデル化の重要性
    • システムリスクと動学の理解、および、取り得る政策対応のカリブレーションのためにそうしたモデル化が重要なものとなる可能性が高い
  3. リスク管理のためには、ティンバーゲンルール的なものが適用される可能性が高い
    • リスクを効果的に監視し管理するために、システムのシステムの複雑なサブコンポーネントと少なくとも同数の政策手段が必要となるだろう
    • 換言すれば、過少識別された複雑なシステムのシステムは、制御不能に陥る可能性が高い。


*2cf. 関連日本語文献