USDA's Office of the Chief Economist published its methodology for estimating trade damage used to set payment rates and purchase levels for the July 25, 2019 farm support package. The calculation covers commodities with assessed retaliatory tariffs from China, India, the European Union, and Turkey.
The published methodology explains how payment rates were set, which affects expected farm cash flow and the pace of commodity marketing. It does not itself change export demand or prices.
After 554 past neutral policy events, Soybeans moved a median +0.0% over 5 sessions (51% higher; middle half -1.4% to +1.6%), and +0.6% over 20.
After 439 past neutral policy events, Corn moved a median +0.1% over 5 sessions (51% higher; middle half -1.3% to +1.2%), and +1.1% over 20.
Moves of each commodity's benchmark from the last close before the event. Historical reads pool past events of the same kind; they describe what happened, not what will. Not investment advice.