Aleh Tsyvinski

Optimal Indirect and Capital Taxation

In this paper, we consider an environment in which agents? skills are private information, are potentially multi-dimensional, and follow arbitrary stochastic processes. We allow for arbitrary incentive-compatible and physically feasible tax schemes. We prove that it is typically Pareto optimal to have positive capital taxes. As well, we prove that in any given period, it is Pareto optimal to tax consumption goods at a uniform rate.

Optimal Taxes on Fossil Fuel in General Equilibrium

We analyze a dynamic stochastic general-equilibrium (DSGE) model with an externality—through climate change—from using fossil energy. Our central result is a simple formula for the marginal externality damage of emissions (or, equivalently, for the optimal carbon tax). This formula, which holds under quite plausible assumptions, reveals that the damage is proportional to current GDP, with the proportion depending only on three factors: (i) discounting, (ii) the expected damage elasticity (how many percent of the output flow is lost from an extra unit of carbon in the atmosphere), and (iii) the structure of carbon depreciation in the atmosphere. Thus, the stochastic values of future output, consumption, and the atmospheric CO2 concentration, as well as the paths of technology (whether endogenous or exogenous) and population, and so on, all disappear from the formula. We find that the optimal tax should be a bit higher than the median, or most well-known, estimates in the literature. We also formulate a parsimonious yet comprehensive and easily solved model allowing us to compute the optimal and market paths for the use of different sources of energy and the corresponding climate change. We find coal—rather than oil—to be the main threat to economic welfare, largely due to its abundance. We also find that the costs of inaction are particularly sensitive to the assumptions regarding the substitutability of different energy sources and technological progress.

Decentralized trading with private information

The paper studies how asset prices are determined in a decentralized market with asymmetric information about asset values. We consider an economy in which a large number of agents trade two assets in bilateral meetings. A fraction of the agents has private information about the asset values. We show that, over time, uninformed agents can elicit information from their trading partners by making small offers. This form of experimentation allows the uninformed agents to acquire information as long as there are potential gains from trade in the economy. As a consequence, the economy converges to a Pareto efficient allocation.

Dynamic Strategic Information Transmission

This paper studies strategic information transmission in a dynamic environment where, each period, a privately informed expert sends a message and a decision maker takes an action. Our main result is that, in contrast to a static environment, full information revelation is possible. The gradual revelation of information and the eventual full revelation is supported by the dynamic rewards and punishments. The construction of a fully revealing equilibrium relies on two key features. The first feature is that the expert is incentivized, via appropriate actions, to join separable groups in which she initially pools with far-away types, then later reveals her type. The second feature is the use of trigger strategies. The decision maker is incentivized by the reward of further information revelation if he chooses the separation-inducing actions, and the threat of a stop in information release if he does not. Our equilibrium is non-monotonic. With monotonic partition equilibria, full revelation is impossible.

A Theory of Asset Prices Based on Heterogeneous Information

We propose a theory of asset prices that emphasizes heterogeneous information as the main element determining prices of different securities. Our main analytical innovation is in formulating a model of noisy information aggregation through asset prices, which is parsimonious and tractable, yet flexible in the specification of cash flow risks. We show that the noisy aggregation of heterogeneous investor beliefs drives a systematic wedge between the impact of fundamentals on an asset price, and the corresponding impact on cash flow expectations. The key intuition behind the wedge is that the identity of the marginal trader has to shift for different realization of the underlying shocks to satisfy the market-clearing condition. This identity shift amplifies the impact of price on the marginal traders expectations. We derive tight characterization for both the conditional and the unconditional expected wedges. Our first main theorem shows how the sign of the expected wedge (that is, the difference between the expected price and the dividends) depends on the shape of the dividend payoff function and on the degree of informational frictions. Our second main theorem provides conditions under which the variability of prices exceeds the variability for realized dividends. We conclude with two applications of our theory. First, we highlight how heterogeneous information can lead to systematic departures from the Modigliani-Miller theorem. Second, in a dynamic extension of our model we provide conditions under which bubbles arise.

Prizes and patents: using market signals to provide incentives for innovations

We consider environments in which agents other than innovator receive the signals about the quality of innovation. We study whether mechanisms can be found which exploit market information to provide appropriate incentives for innovation. If such mechanisms are used, the innovator has incentives to manipulate market signals. We show that if an innovator cannot manipulate market signals, then the efficient levels of innovation can be uniquely implemented without deadweight losses – for example, by using prizes. Patents are necessary if the innovator can manipulate market signals. For an intermediate case of costly signal manipulation, both patents and prizes may be optimal.

Energy Sector Quasi-Fiscal Activities in the Countries of the Former Soviet Union

A decade into the transition, many of the successor states of the former Soviet Union (FSU) continue to use energy sector quasi-fiscal activities (QFAs), especially low energy prices and the toleration of payment arrears, to provide large implicit and untargeted subsidies. These activities disguise the overall size of the government, cause overconsumption and waste, and contribute to macroeconomic imbalances. This paper analyses such activities in FSU countries, with particular emphasis on two case studies (Azerbaijan and Ukraine). The papers policy conclusions point to the need to increase energy prices, combined with a strengthening of safety nets to protect the poor, better enforcement of payment discipline, and more efforts to achieve fiscal transparency.

Information Aggregation, Investment, and Managerial Incentives

We study the interplay of share prices and firm decisions when share prices aggregate and convey noisy information about fundamentals to investors and managers. First, we show that the informational feedback between the firms share price and its investment decisions leads to a systematic premium in the firms share price relative to expected dividends. Noisy information aggregation leads to excess price volatility, over-valuation of shares in response to good news, and undervaluation in response to bad news. By optimally increasing its exposure to fundamental risks when the market price conveys good news, the firm shifts its dividend risk to the upside, which amplifies the overvaluation and explains the premium. Second, we argue that explicitly linking managerial compensation to share prices gives managers an incentive to manipulate the firms decisions to their own benefit. The managers take advantage of shareholders by taking excessive investment risks when the market is optimistic, and investing too little when the market is pessimistic. The amplified upside exposure is rewarded by the market through a higher share price, but is inefficient from the perspective of dividend value.

Optimal Fiscal and Monetary Policy (without commitment)

Most of the results of optimal taxation literature in the Ramsey framework are derived under the assumption of commitment. Commitment is usually defined as ability of a government to bind future policy choices. This assumption is restrictive. A government, even a benevolent one, may choose to change its policies from those promised at an earlier date. The first formalization of the notion of time inconsistency is due to Kydland and Prescott (1977), who showed how timing of government policy may change economic outcomes. Furthermore, equilibrium without commitment can lead to lower welfare for society than when a government can bind its future choices.

POLITICAL ECONOMY OF INTERMEDIATE GOODS TAXATION

We generalize the Diamond-Mirrlees production efficiency theorem, that there should be no taxes on sectors producing pure intermediate goods, to an environment with political economy constraints. In our economy, allocations and taxation are decided by self-interested politicians without the power to commit to future policies. The Diamond-Mirrlees production efficiency result holds even when political economy constraints introduce distortions on labor supply and capital accumulation. (JEL: H11, H21, E61, P16) (c) 2008 by the European Economic Association.