Utility Maximization with Proportional Transaction Costs Under Model Uncertainty

We consider a discrete time financial market with proportional transaction costs under model uncertainty and study a numéraire-based semistatic utility maximization problem with an exponential utility preference. The randomization techniques recently developed in Bouchard, Deng, and Tan [Bouchard B, Deng S, Tan X (2019) Super-replication with proportional transaction cost under model uncertainty. Math. Finance 29(3):837–860.], allow us to transform the original problem into a frictionless counterpart on an enlarged space. By suggesting a different dynamic programming argument than in Bartl [Bartl D (2019) Exponential utility maximization under model uncertainty for unbounded endowments. Ann. Appl. Probab. 29(1):577–612.], we are able to prove the existence of the optimal strategy and the convex duality theorem in our context with transaction costs. In the frictionless framework, this alternative dynamic programming argument also allows us to generalize the main results in Bartl [Bartl D (2019) Exponential utility maximization under model uncertainty for unbounded endowments. Ann. Appl. Probab. 29(1):577–612.] to a weaker market condition. Moreover, as an application of the duality representation, some basic features of utility indifference prices are investigated in our robust setting with transaction costs.

Transaction Costs and Farm-to-Market Linkages in China: Empirical Evidence from Apple Producers

Using field surgveyed data from two apple production belts in China, this study estimates the impact of transaction costs on smallholders’ market participation and integration. The analysis is based on an innovative measurement of the transaction costs and a disaggregated analysis of sales, information, negotiation, and monitoring costs. The results reveal that farmers’ market participation levels are mainly determined by the proportional transaction costs and price, while their market integration depends on the fixed transaction costs and price. This suggests that, to lower the transaction costs and enable specialization and market participation, it is necessary to invest in and construct adequate farming infrastructure, update the rural information system, improve the structure of farmer households, and subsidize specialized rural cooperative organizations.