XIU invests in the Canadian large-cap space. The fund tracks an index in which the investment universe has been selected by an investment committee. Eligible securities from the S&P/TSX Composite are screened by market cap and liquidity, 60 of the largest companies are included in the index. Sectors weights are intended to parallel the S&P/TSX Composite. The index usually undergoes quarterly rebalance. XIU currently employs a replicating strategy wherein it invests in securities in considerably the same proportions as they are represented in the index. The origins of this fund date back to the first ETF in the world to be offered. The fund originally launched on March 9, 1990 as the Toronto 35 Index Participation Fund, tracking the TSX 35 Index. On September 26, 1999 the fund merged with Hundred Index Participation Fund which tracked the TSX 100 Index and was named iUnits S&P/TSX Index Participation Fund. On March 7, 2000, the fund was renamed to its current reference.