城市化、结构变动与农业发展——基于城乡两部门的动态一般均衡分析

本文认为,地方政府和企业之间的合谋是中国经济的高增长率和高事故率并存的原因。我们刻画了最优的防范合谋契约,在该契约下地方政府和企业拥有正的信息租金,防范合谋将给中央政府带来额外的成本。在临界值以下,赔偿金具有部分地替代监督和惩罚的作用。以最优的防范合谋契约为基准,我们解释了造成当前政企合谋大量存在的若干重要原因:中央政府防范合谋的成本太高、地方政府缺乏长远预期、企业被过度抽税、第四方监督失效和惩罚不可置信等。     

Collusion and Renegotiation in a Principal–Supervisor–Agent Relationship

We describe a principal–supervisor–agent relationship in which agent and supervisor may collude. To prevent collusion, the principal may contract on a noisy signal which is correlated with the occurrence of collusion. When the signal is informative enough, the principal uses it and no collusion occurs in equilibrium. These contracts, however, are ex post inefficient and are only optimal if the principal can commit not to renegotiate. With renegotiation it is never optimal for the principal to prevent collusion and, at the same time, condition contracts on the signal. In fact, when the signal is informative enough collusion occurs in equilibrium.     

Does R&D cooperation facilitate price collusion? An experiment

We examine in a laboratory experiment whether R&D cooperation facilitates tacit price collusion. For two scenarios of technological spillovers, a baseline treatment without binding contract possibilities and a contract treatment where it is possible to credibly commit to an R&D contract, are run. We find that the degree of price collusion in the contract treatments is significantly higher in periods where R&D contracts are made than in periods without contracts, and than in the baseline treatments.     

The effects of imperfect auditing on managerial compensation

We study the optimal shareholder–manager contract having the property to induce the manager to exert high effort and truthfully reveal firm performance. This contract design problem is solved under the assumption of imperfect auditing, either because of mistakes or because of collusion between managers and auditors. The imperfection of the audit technology is costless up to a threshold, beyond which it causes a distortion in the incentive compatible contract or even prevents its existence. This result may help explain the observed decline in the use of stock options, tracing it back to an unfocused activity or poor performance of auditors.     

Efficiency versus collusion: a reformulation of the Weiss test

The weiss test has been used to discriminate between the efficiency and collusion hypotheses. Using a conventional oligopoly model, we show that the test is valid for the former hypothesis but not the latter. Contrary to recent emperical studies, we find that a negative coefficient on concentration in profitability equations does not refute the collusion hypothesis. In fact, this finding supports the hypothesis if the sample is dominated by small firms.     

Global public goods and coalition formation under matching mechanisms

This paper links coalition theory with matching mechanisms in the presence of global public goods among heterogeneous players. This matching coalition may achieve Pareto‐improving outcomes while avoiding side payments. The paper characterizes conditions of coalition profitability and stability at both interior and corner equilibria. It is generally much harder to satisfy stability conditions than profitability conditions. A matching coalition is more profitable but less stable with a larger matching rate. Empirically there is no stable coalition but this can be overcome by introducing reputation mechanisms. There always exists a stable grand matching coalition if players value their reputation. The matching coalition faces a trade‐off between matching depth and breadth.     

Collusive dominant-strategy truthfulness

We show that collusion and wrong beliefs may cause a dramatic efficiency loss in the Vickrey mechanism for auctioning a single good in limited supply. We thus put forward a new mechanism guaranteeing efficiency in a very adversarial collusion model, where the players can partition themselves into arbitrarily many coalitions, exchange money with each other, and perfectly coordinate their actions. Our mechanism bypasses classic impossibility results (such as those of Green and Laffont, and of Schummer) by providing the players with a richer set of strategies, making it dominant for every coalition C to instruct each of its members to report truthfully not only his own valuation, but also his belonging to C. Our mechanism is coalitionally rational, which implies being individually rational for independent players.     

Preemptive collusion among corruptible law enforcers

This paper considers collusion between a supervisor and an agent within a Principal–Supervisor–Agent model. Other papers consider the possibility of collusion after the supervisor has exerted costly effort to obtain hard (“verifiable”) evidence regarding the agent’s actions, information which, if reported would result in the agent being fined with a certain probability. That is, collusion occurs because the supervisor may accept a bribe in exchange for hiding the information he has obtained. This paper allows the supervisor and the agent to enter into a collusive contract either before or after the supervisor has exerted effort to find verifiable information regarding the agent’s actions. The former type of collusion, which occurs after the supervisor has exerted effort, entails ex-post corruption, while the latter, which occurs before the supervisor has exerted effort, entails preemptive corruption. This paper shows that although raising the supervisor’s reward discourages ex-post corruption, it can simultaneously encourage preemptive corruption. Hence, raising the supervisor’s reward will not always discourage collusion. This result further implies that though privatizing law enforcement can always be used to eliminate ex-post corruption, it cannot be used to eliminate preemptive corruption. Furthermore, when compared to ex-post collusion, an equilibrium without corruption is always socially preferred. However, when compared to preemptive collusion, an equilibrium without corruption may not always be socially preferred.     

Bidder collusion

We analyze bidder collusion at first-price and second-price auctions. Our focus is on less than all-inclusive cartels and collusive mechanisms that do not rely on auction outcomes. We show that cartels that cannot control the bids of their members can eliminate all ring competition at second-price auctions, but not at first-price auctions. At first-price auctions, when the cartel cannot control members’ bids, cartel behavior involves multiple cartel bids. Cartels that can control bids of their members can suppress all ring competition at both second-price and first-price auctions; however, shill bidding reduces the profitability of collusion at first-price auctions.     

Fighting collusion by regulating communication between firms

This paper is an attempt to create a coherent approach to the design of competition policy enforcement against collusion based on theoretical considerations, evidence from economic experiments, and case studies. I argue that collusion should primarily be fought indirectly by targeting types of communication between firms that are particularly likely to facilitate collusion. In particular, I identify types of communication which have high potential anti-competitive effects but where it is unlikely that prohibiting communication will lead to efficiency losses. This analysis leads to some simple rules concerning communication between firms, which could also guide the development of competition rules for B2B electronic market places.
— Kai-Uwe Kühn     

Tacit collusion in repeated auctions

This paper considers the question of tacit collusion in repeated auctions with independent private values and with limited public monitoring. McAfee and McMillan show that the extent of collusion is tied to the availability of transfers. Monetary transfers allow cartels to extract full surplus. A folk theorem proved by Fudenberg et al. (Econometrica 62 (1994) 997-1039) shows that transfers of future payoffs are almost as good if players are patient and communicate before auctions. We ask how the scope of collusion is affected if players dispense with explicit communication and their monitoring is limited. Collusion better than bid rotation is still feasible, but full surplus cannot be extracted. This constraint becomes less severe with more players and large cartels can become asymptotically efficient even with very limited monitoring.     

基于“囚徒困境”博弈的防范工程招投标合谋研究

提出一种防范工程招投标中招标代理与投标人合谋的新策略,即同时派出两个招标代理审查投标人,使两个招标代理陷入"囚徒困境"博弈中以保证其报告真实。进而针对该策略成本太高的缺点,通过使两者处于不对称信息环境下,进一步改进了该"囚徒困境"博弈。据此,只要招标人设定适当的奖励和惩罚机制,就能在一定程度上阻止招标代理与投标人合谋。     

Excluded coalitions and the distribution of power in parliaments

In this article, we introduce a new value for cooperative games. This value is based on the Shapley (1953) value and takes into account that players exclude coalitions with other players. One example of such exclusions are the coalition statements of parliamentary parties. A case study demonstrates the application of the new value for these situations.     

Analysis of vertical separation of regulators under adverse selection

We analyze the vertical separation of a regulator when a government delegates the task to monitor a regulated firm to an intermediate institution called a “middleman”. We deal with the double adverse selection problem between the government and the middleman, and between the middleman and the firm. We reach three main conclusions. First, we clarify the condition under which vertical separation is socially superior to vertically integrated regulation. Second, we show that when the middleman and the firm are able to collude by using a side contract, collusion can lead to information-sharing effects that enhance social welfare. Third, it is socially desirable for the government to offer a collusion-proof contract to the middleman if the collusion inefficiency is much larger than the expected socially desirable information-sharing effects.      

Elimination contests with collusive team players

We consider a standard two-stage elimination (Tullock) contest where multiple (team) players can perfectly and publicly collude with each other throughout. We analyze and compare equilibrium outcomes under various seedings where the collusive players meet or are separated in the group stage. We identify the impact of collusion on the contest organizer and non-collusive players, as well as the organizer's optimal seeding. We find that collusion, while always undermining fairness of the competition, can hurt or benefit the organizer, depending on the discriminatory powers of the two stages. We also discuss issues such as sequential group-stage competitions, comparison between the elimination contest and the corresponding one-shot contest, secret collusion, and large discriminatory powers.     

Why did UK manufacturing profitability rise over the 1980s?

Profitability in UK manufacturing collapsed in the early 1980s, but then recovered to 1970s levels. To account for the changes in profits we propose a series of extensions of the widely-used Cowling and Waterson (1976) model. Our extensions incorporate demand shocks, varying competition and collusion, and the role of unions. The resulting model encompasses Cowling/Waterson, the Kreps and Scheinkman (1983) varying competition model and the Green and Porter (1984) and Rotemberg and Saloner (1986) varying collusion models. Using a panel of 53 UK industries, 1973–1986 we estimate the encompassing model by generalised methods of moments/instrumental variables. Our major findings are: (a) there is no substantial contribution to changes in aggregate profitability from the batting average effect of movements between sectors; (b) the collapse of profits in the early 1980s was mainly driven by the collapse in demand; (c) the fall in union density in the 1980s has increased profitability despite a fall in concentration. We also find tentative evidence suggesting that collusion is pro-cyclical as in Green and Porter (1984).For very useful comments I thank Josef Falkinger, Paul Geroski and David Audretsch. I thank Chris Martin for letting me use much of our joint work and Ian Small for the data.     

Merger policy,entry, and entrepreneurship

We assess the impact of merger policy on entry and entrepreneurship. When faced with uncertainty about its prospects, and foreseeing that it may wish to leave the market should profitability prove poor, a rational entrant considers possible exit routes. Horizontal merger reduces competition post-merger which, all else being equal, lowers welfare; but merger also provides a valuable exit route. By facilitating exit and thus raising the value of entry, more lenient merger policy may stimulate entry sufficiently that welfare is increased overall. We calculate the optimal merger policy in the form of a low, but positive, profitability threshold below which merger is permitted despite the adverse impact on post-merger competition. This may be viewed as an extension of the “failing firm defence” to include ailing, low profitability firms as well as imminently failing ones. Merger policy is compared with an entry subsidy, and the implications of strategic firm behaviour for the choice of merger policy are also examined.     

Extinction in common property resource models: an analytically tractable example

We discuss an analytically tractable discrete-time dynamic game in which a finite number of players extract a renewable resource. We characterize a symmetric Markov-perfect Nash equilibrium of this game and derive a necessary and sufficient condition under which the resource does not become extinct in equilibrium. This condition requires that the intrinsic growth rate of the resource exceeds a certain threshold value that depends on the number of players and on their time-preference rates.     

FINITELY REPEATED PRISONERS' DILEMMA WITH SMALL FINES: THE PENANCE CONTRACT*

This paper investigates finitely repeated prisoners' dilemma games with explicit contractual devices. It shows that full collusion can be achieved in a unique manner by incentivizing the players' final‐period play with small fines. The incentivizing modality is the penance contract, by which a player is penalized if and only if he deviates from the penance strategy in the final period. Using this contractual agreement brings the penance strategy profile into unique subgame perfect equilibrium in the entire game and achieves full collusion without being invalidated by renegotiation.     

Winners and losers from financial derivatives use: evidence from community banks

This article provides empirical evidence on how profitability of small community banks was affected by derivatives use before and after the 2008 crisis. We use an endogenous switching regressions model to estimate the sensitivity of bank profitability to risks and control for the endogenous choice to use or not to use derivatives. We then compute counterfactual effects and show how profitability would have looked without derivatives use for banks that used derivatives and how it would have looked with derivatives for banks that did not use derivatives. The results show that derivatives helped reduce the sensitivity of profitability to credit risks and improved profitability for most specialists. However, for the largest number of banks which are non-user non-specialists, devivates use would have resulted in lower return on assets had they used derivatives post 2008. Therefore, our evidence suggests that implementation of the Volcker Rule, imposing high compliance costs on community banks and, thus, discouraging hedging, may have a negative impact on profits of specialists banks but, overall, a neutral effect on profits in the community banks industry as a whole.