The problem with a FTT is that it is a cascading tax. Whereas a VAT or GST is charged only on the difference between input and output. I buy some wood for $10,

The problem with a FTT is that it is a cascading tax. Whereas a VAT or GST is charged only on the difference between input and output. I buy some wood for $10, make a table, sell it for $15, GST/VAT is 10%, so I pay out $1 buying the wood, and collect $1.50 selling the table. I only have to forward the difference, 50c, to the government. With an FTT, that 'tiny' tax is charged indiscriminately all the way through the chain. And passed through the chain to the end consumer. So the market maker pays it twice (in and out of a position) and their margins are razor thin. So spreads will increase by twice the tax for starters. Plus you as end consumer will pay it twice (on buying and selling). So at a bare minimum that 0.1% will be 0.4% for an end consumer. More if more middlemen are involved in the chain, since it just compounds. What are annual returns? 4-8%? So we're talking about the government taking 5-10% of your profits? Does it seem tiny still?