The Spahn tax is like a special type of taxes that businesses have to pay if they want to make some profits from the stock market. It's a tax on the profits businesses make from buying and selling stock. The tax was named after its creator, William Spahn, who wanted to make sure that stocks were being balanced fairly - so that everyone could have access to the same level of stock profits. This tax helps to make sure that no one can get too much of an advantage by buying and selling stocks.