Basket trading is a pretty advanced portfolio rebalancing strategy used in the stock market by portfolio managers. They basically put instruments from several asset classes in a "basket" and execute the trade at once.
For example, is a portfolio manager is trying to rebalance his portfolio he will sell of some instruments and buy some at the same time. If you know when this rebalancing is happening, you can take advantage of the volatility it will cause in the forex market because he has to use money to buy these instruments.
