Designing social security - a portfolio choice approach

Public social security systems may provide diversification of risks to individuals’ life-time income. Capturing that a pay-as-you-go system (paygo) may be considered as a “quasi-asset”, we study the optimal size of the paygo system as well as the optimal split between funded and unfunded pension saving by means of a theoretical portfolio choice framework. A low-yielding paygo system can benefit individuals if it contributes to hedge other risks to their lifetime resources. Numerical calculations indicate that optimal social security systems should be at least partly paygo financed in many economies. The optimal magnitude of the paygo system depends on the specified risk concept as well as the stochastic properties of stock market returns and implicit paygo-returns.     

Time to default in the UK mortgage market

This paper employs duration analysis to investigate the timing of default in the UK mortgage market. Our analysis is performed on an ex ante basis, in that our explanatory variables are available to mortgage lenders when the loan is first made. We estimate both standard Weibull distributions and generalizations of the Weibull that permit non-monotonic hazard functions. The models fit the data well, suggesting that we have captured the major sources of variation in duration. We find that ‘cash flow’ variables, such as salary and interest rate paid, play the largest role. Surprisingly, loan-to-value ratios are either insignificant or influence default times in a counter-intuitive direction.     

The structural transformation and aggregate productivity in Portugal

We document the substantial process of structural transformation—the reallocation of labor between agriculture, manufacturing, and services—and aggregate productivity growth undergone by Portugal between 1956 and 1995. We assess the quantitative role of sectoral labor productivity in accounting for these processes. We calibrate a model of the structural transformation to data for the United States and use the model to gain insight into the factors driving the structural transformation and aggregate productivity growth in Portugal. The model implies that Portugal features low and roughly constant relative productivity in agriculture and services (around 22%) and a modest but growing relative productivity in manufacturing (from 44 to 110%). We find that productivity growth in manufacturing accounts for most of the reduction of the aggregate productivity gap with the United States and that a further closing of this gap can only be accomplished via improvements in the relative productivity of services. This paper was written while the authors were affiliated with the Federal Reserve Bank of Richmond. We would like to thank the editor, two anonymous referees, and participants at the Third Conference on Portuguese Economic Development in the European Context organized by the Bank of Portugal for their comments. All errors are our own.     

On the evolutionary edge of altruism: a game-theoretic proof of Hamilton’s rule for a simple case of siblings

We offer a game-theoretic proof of Hamiltons rule for the spread of altruism. For a simple case of siblings, we show that the rule can be derived as the outcome of a one-shot prisoners dilemma game between siblings.JEL Classification: A13, C70, D64Correspondence to: Oded Stark, ZEF, University of Bonn, Walter-Flex-Strasse 3, 53113 Bonn, GermanyWe are indebted to an anonymous referee and to Uwe Cantner for helpful comments and suggestions. Partial financial support from the National Institute on Aging (grant RO1-AG13037) and from the Humboldt Foundation is gratefully acknowledged.     

Representative consumer's risk aversion and efficient risk-sharing rules

We study the representative consumer's risk attitude and efficient risk-sharing rules in a single-period, single-good economy in which consumers have homogeneous probabilistic beliefs but heterogeneous risk attitudes. We prove that if all consumers have convex absolute risk tolerance, so must the representative consumer. We also identify a relationship between the curvature of an individual consumer's individual risk sharing rule and his absolute cautiousness, the first derivative of absolute risk-tolerance. Furthermore, we discuss some consequences of these results and refinements of these results for the class of HARA utility functions.     

BANK INTEREST MARGINS AND BUSINESS START-UP COLLATERAL: TESTING FOR CONVEXITY

The paper investigates the relationship between bank interest rate margins and collateral for loans issued to new ventures. The analysis finds a convex U‐shaped relationship. The results indicate that while provision of collateral initially reduces bank exposure to risk (through security, more optimal levels of capital and lower moral hazard among entrepreneurs) that beyond a point, the positive risk‐wealth association gives rise to greater risk taking propensity among entrepreneurs and ultimately higher interest rates. This indicates that a lender's pricing policy may even somewhat help to level the competitive playing field between ventures launched by higher and moderately wealthy entrepreneurs.     

Foreign direct investment, competition and industrial development in the host country

This paper analyses the impact of foreign direct investment (FDI) on the development of local firms. We focus on two likely effects of FDI: A competition effect which deters entry of domestic firms and positive market externalities which foster the development of local industry. Using a simple theoretical model to illustrate how these forces work we show that the number of domestic firms follows a u-shaped curve, where the competition effect first dominates but is gradually outweighed by positive externalities. Evidence for Ireland tends to support this result. Specifically, applying semi-parametric regression techniques on plant level panel data for the manufacturing sector we find that while the competition effect may have initially deterred local firms’ entry, this initial effect has been outpaced by positive externalities making the overall impact of FDI largely positive for the domestic industry.     

Herding in delegated portfolio management: When is comparative performance information desirable?

We address the issue of investors’ asset allocation decisions when portfolio management is delegated to an agent. Contrary to predictions from traditional financial theory, it is shown that investors may not induce their manager to allocate funds to the asset with the highest return. Instead they may herd in their asset allocation decision and induce trade in a particular asset, because another manager is trading in it and despite the presence of a more profitable alternative. Doing so allows investors to write an efficiency-improving relative-performance contract. On the other hand, herding leads investors to design wage contracts strategically, resulting in more aggressive and thus less profitable trade in equilibrium. We show that herding occurs, when the cost of information is high, information precision is low and when managers are sufficiently risk averse. Moreover, when investors can decide whether or not to disclose information about their manager's performance, they will not do so.     

Returns of Small Growth Stocks: An Empirical Analysis

I investigate the mean reversion tendency of small growth stocks. Using a carefully articulated research design employing established and empirically tested principles, my findings should support or refute the anecdotal evidence that small growth stocks make superior investments. The primary motivation for the study springs from the documented differential preference among investors for value and growth stocks. Despite evidence that value stocks tend to outperform growth stocks, investors retain strong interest in growth stocks. Yet in examining the performance of Business Week’s (BW), smaller capitalization companies (called “Hot Growth Companies”) with respect to the overall financial market, Bauman et al. [2002] found positive excess returns in the pre-publication period but negative excess returns in the post-publication period. A limitation of their study is that their analyses relied on only three criteria: sales, BW rank and return on capital, which do not represent completely a firm’s financial health. I replicate Bauman et al.’s study but use a more robust and representative variable set to test the mean reversal hypothesis — Forbes’ financial criteria — and I focus on six variables. In the current study, I look at 4,200 companies listed in Forbes from 1980 to 2000. The results of the expanded study substantiate Bauman et al.’s [2002] study showing that there are positive excess returns in the pre-publication period, but negative excess returns in the post-publication period. An expanded future study will look at five additional variables to see if they make a significant difference on the effects of the returns of small growth stocks.     

THE JOINT ARRIVAL AND DEPARTURE PROCESS FOR THE M/M/l QUEUE

We consider the M/M/1-queue and derive an explicit expression for the joint distribution of the number of arrivals and the number of departures in [0, t), given the number of customers initially present. The derivation is almost purely combinatorial, it avoids the use of generating functions, and immediately yields a simple probabilistic interpretation of the result.