Market Sharing Agreements and Collusive Networks

This paper analyzes the formation of market sharing agreements among firms in oligopolistic markets and procurement auctions. The set of market sharing agreements defines a collusive network, and the paper provides a complete characterization of stable and efficient collusive networks when firms and markets are symmetric. Efficient networks are regular networks, where firms have the same number of market sharing agreements. Stable networks are formed of complete alliances, of different sizes, larger than a minimal threshold. Typically, stable networks display fewer market sharing agreements than the optimal network for the industry and more market sharing agreements than the socially optimal network. When firms or markets are asymmetric, incomplete alliances can form in stable networks, and stable networks may be underconnected with respect to the social optimum.Market sharing, Collusion, Economic networks, Oligopoly, Auctions

Optimal Ownership Structures in Asymmetric Joint Ventures

This paper investigates the relation between asymmetries in the distribution of shares in joint ventures and asymmetries between the parent companies. When the joint venture and the parent companies are controlled by separate entities, we provide a simple formula to compute the optimal ownership structure. This formula is applied to various models of market interaction, showing that larger companies should have a larger fraction of shares, and so should companies whose goods are closer substitutes of the product of the joint venture, or companies who have a higher cost of transformation of the input produced by a joint venture.Joint ventures, Strategic alliances, Ownership structure, Asymmetries

Australian coal mining: Estimating technical change and resource rents in a translog cost function

This paper estimates a translog cost function for the Australian coal industry from 1968/69 to 2004/05. We use a variable measuring the shift to open-pit mining to capture the impact of embodied technical change, while using a time trend to capture the impact of other technical change and changing resource rents. The cost function is estimated with Zellner's SUR procedure. The shift to open-cut mining is shown to be important in lowering cost during the 1970s and 1980s, but more recently cost reduction is captured by the time trend

Childhood Obesity, Cortical Structure, and Executive Function in Healthy Children.

The development of executive function is linked to maturation of prefrontal cortex (PFC) in childhood. Childhood obesity has been associated with changes in brain structure, particularly in PFC, as well as deficits in executive functions. We aimed to determine whether differences in cortical structure mediate the relationship between executive function and childhood obesity. We analyzed MR-derived measures of cortical thickness for 2700 children between the ages of 9 and 11 years, recruited as part of the NIH Adolescent Brain and Cognitive Development (ABCD) study. We related our findings to measures of executive function and body mass index (BMI). In our analysis, increased BMI was associated with significantly reduced mean cortical thickness, as well as specific bilateral reduced cortical thickness in prefrontal cortical regions. This relationship remained after accounting for age, sex, race, parental education, household income, birth-weight, and in-scanner motion. Increased BMI was also associated with lower executive function. Reduced thickness in the rostral medial and superior frontal cortex, the inferior frontal gyrus, and the lateral orbitofrontal cortex partially accounted for reductions in executive function. These results suggest that childhood obesity is associated with compromised executive function. This relationship may be partly explained by BMI-associated reduced cortical thickness in the PFC.Wellcome Trust Bernard Wolfe Health Neuroscience Fun