Bill & Caldwell were the importers for Borsalino in America. The following are transcripts of their testimony at Fur Felt Hats Tariff, Readjustment (U.S. Congress) hearings of 1929. The total imports for 1927 Men's Fur Felt Hats were 28,500 dozen which made up only about 1% of the United States Men's Fur Felt Hat Market so very tiny. Regardless the American Fur Felt Hat Industry wanted to increase tariffs. Italy had 18,000 dozen of the 28,000 dozen and most were from Borsalino (reason for Bill & Caldwell and others testimonies of the behalf of Borsalino).
Fur Felt Hats Tariff, Readjustment 1929 (U.S. Congress) (Scroll down to "Statement of J.G. Whitelaw, ....")
You might want read the entire hearing from the beginning. It's pretty interesting with some funny exchanges. The hearing also includes Women's Fur Felt Hats (a larger number, 94,825 dozen) which were largely Velours from Austria and Czechoslovakia.
The testimony by J.G. Whitelaw representing Bill & Caldwell is interesting. He mentions the selling point for Borsalinos was their light weight but the tariffs were making them 2 to 4 dollars ($12.00) more than equal price point American hats ($8.00) so this making them too expensive and impacting sales. He said they were 1% of the Men's Fur Felt Hats so they were no threat to the American Men's Furt Felt Industry. The counter from the U.S. side was the imports were increasing and they wanted to increase the tariff. Seems ridiculous but I guess they saw that Italy and Europe in general were not importing U.S. made Fur Felt Hats and didn't like that.
In the other parts of the hearing the very small wages being paid to Italian workers is brought up. I guess the point was that Italian companies and Borsalino in particular were making a lot of money on their hats based on the low wages they were paying their employees. The counter argument from the Borsalino side was that there were other factors driving up their costs such as fur, components (sweatbands, liners) and shipping costs. I have no idea if Borsalino / the Italian side was being totally truthful.