A Securities Turnover Excise Tax (STET) is a small tax on every stock, swap, derivative, or other trade. In the United States, the STET was used to successfully fund the Spanish American War. Re-instatement of the STET was briefly proposed in 1990, as a part of US deficit reduction measures. John Maynard Keynes, in The General Theory of Employment, Interest, and Money suggested that an excise tax on transactions and trades would discourage speculation in the stock market.