Yuhan Wang

Research

Job Market Paper

Supply Networks and Market Power in U.S. Poultry Procurement

Job Market Paper

How do supplier networks and firm ownership shape pricing and the burden of supply disruptions? I construct the first model of a shipment-based U.S. poultry procurement network, linking processing plants to county procurement markets and firm ownership. Annual plant-to-county network densities average 10 percent for retailer-bound shipments and 14 percent for wholesaler-bound shipments. A demand-and-supply model with joint pricing across each processor’s plants recovers a baseline price–cost margin of 33 percent of the selling price. Wholesale buyers are 1.67 times as price sensitive as retail buyers and 3.33 times as price sensitive as food-service buyers. A 20 percent raw-poultry cost increase lowers total surplus by 17.7 percent and reduces both buyer and processor surplus. A merger of the third- and fourth-largest processors raises prices by 6.9 percent and increases processor surplus while reducing buyer and total surplus; 59 percent of the buyer loss is deadweight loss. The regional burden is related to the demand that a market serves. Controlling for income, education, and population, a 10-percentage-point higher baseline share of county procurement shipped to wholesalers is associated with procurement losses that are 6 percent larger in pounds and buyer-surplus losses that are 4 percent larger in dollars under the input-cost shock, without a statistically detectable additional price response.

Paper (PDF)

Working Papers

A Text-Based Measure of Farm Bill Uncertainty and Its Effects on Agricultural Credit

Revision requested at Journal of Agricultural Economics.

This paper develops a Farm Bill Uncertainty Index using a two-stage BERT classifier that isolates newspaper language reflecting legislative delay, disagreement, and procedural impasse. The index tracks negotiation cycles, spiking during conflict and declining after enactment. Merging the index with institution-level data for commercial banks, credit unions, and Farm Credit System institutions shows that higher uncertainty reduces agricultural lending, most clearly for commercial banks: a 0.10 increase in the index is associated with about a 0.37 percent decline in lending. Exposure-weighted and stacked difference-in-differences estimates further show that lending expands more rapidly after uncertainty declines.

Paper (PDF)

Climate-Conditioned Comparative Advantage, Persistence, and U.S. Corn–Soy Land Allocation

With Xiaodong Du and Xueying Sun.
Submitted to Journal of Environmental Economics and Management.

This paper studies how climate-conditioned comparative advantage translates into county-level corn–soy land allocation in the U.S. Corn Belt when production patterns are persistent. Using rain-fed potential-yield simulations from FAO Global Agro-Ecological Zones, it constructs a Relative Input Premium Advantage (RIPA) that compares the potential-yield gains from higher-input management for corn and soybeans. RIPA is associated mainly with persistent cross-county differences in allocation, while year-to-year acreage changes are more closely related to expected relative revenues. A discrete-choice land-allocation model with expected portfolio revenue, RIPA, revenue risk, and prior allocation shows strong state dependence: counterfactual acreage responses increase substantially when the estimated persistence penalties are removed, and historical GAEZ shifts between 1990 and 2010 imply modest aggregate reallocation.

Paper (PDF)

Selected Work in Progress