FX INDEX ARB (FXIA) is a systematic, quantitative trading program, which trades currencies in the cash ("spot") markets. The strategy creates a complex portfolio of 10 global (G10) currencies and adjusts its components daily.
The strategy forms indexes of the 10 base currencies, which depend on the prices of the remaining 9 currencies against the selected index currency. It trades (counter trend, short volatility) the components of each index against the index itself (trend following, long volatility). Exactly the same rules are used for trend and counter trend trading. The point is to exploit the difference between the higher volatility of individual components and the lower volatility of indexes (as proven by the Modern Portfolio Theory).
Based on positions of all components and indexes (a total of 90 currency crosses), positions are consolidated into the base 10 currencies, i.e. 9 currency pairs against the US Dollar. The resulting positions are then implemented in the market. The trading strategy is always in the market, but portfolio weights are adjusted daily.