US farmers no longer had guaranteed markets for crops after WWI - crop prices were depressed worldwide.

High tariffs caused a decrease in international trade.

US bank leadership after WWI led to banking collapse that spread rapidly worldwide.

What would be the best title for this list?

The Great Depression

Explanation:

The Great Depression was an economic depression notable for its duration and intensity that struck the world from 1929-1933. Recovery was a long and difficult process.

The causes of the great depression include tariffs decreased on the foreign market for American goods, crisis in the farming industry, Easily available credit, and unequal distribution of wealth.

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