Excellent detective work, Steve. Always nice to be able to add a piece to the puzzle.I solved a mystery (it's been a long while)! Back in 2021 I acquired an Austrian Wool Stiff Felt with no company mark on the liner and sweatband and only this "St. Veit" (a district of Vienna) mark on the paper label. At the time I made many searches and wasn't able to come up with anything.
https://germanaustrianhats.invision...i-wien-hutfabrik/?do=findComment&comment=5384
Yesterday (10/30/24) I was looking through some digital copies of Deutsche Hutmacher Zeitung for trademarks and I came across this trademark in the Jan. 11, 1930 DHZ (see below). I have looked at this trademark page many times but for some reason I missed / overlooked these Bossi Wien "St. Veit" trademarks. It could be I forgot about this Austrian trademark page, when searching for the "St. Veit" mark, because it was in DHZ. (By the way there is also a previous page of German trademarks.)
Notice there are separate trademarks for Fur Felt Hats and Wool Felt Hats.
I have always been on a look out for Bossi Wien Soft and Stiff Felt Hats but I haven't found any in my size and I don't believe I found any from the WWII era or earlier. Here is a Bossi Wien page on my website with more information. There is also a second Bossi Wien Stiff Felt listed that I found back in January.
https://germanaustrianhats.invisionzone.com/topic/2534-bossi-wien-hutfabrik/