An economist proposed taxing every currency trade to slow down panic

In 1972, Nobel laureate James Tobin proposed a small tax on international currency transactions, aimed not at raising revenue but at making rapid speculative in-and-out trading slightly less profitable, to reduce the exchange-rate swings that short-term capital flows can cause. No major economy has adopted it at scale, but the idea resurfaces after nearly every financial crisis.

— James Tobin, The New Economics One Decade Older — Princeton University Press, 1974