This tiny tax on speculative activities takes from the obscenely rich casino style banking practices - that may or may may not have bankrupted the world’s economy – and uses the money for good purposes. Like Robin Hood.
This is a version of the long mooted Tobin tax - click for wiki link
Taken from the wiki article (adapted slightly by me):
No less a luminary than John Maynard Keynes in 1936 (after the Wall street Crash and Great Depression) proposed that a small transaction tax should be levied on dealings on Wall Street, where he argued that excessive speculation by uninformed financial traders increased volatility. For Keynes, who personally enjoyed speculation to the fullest, the key issue was the proportion of ‘speculators’ in the market, and his concern that, if left unchecked, these types of players would become too dominant. Keynes writes:
"Speculators may do no harm as bubbles on a steady stream of enterprise. But the situation is serious when enterprise becomes the bubble on a whirlpool of speculation."
"The introduction of a substantial government transfer tax on all transactions might prove the most serviceable reform available, with a view to mitigating the predominance of speculation over enterprise in the United States."