This means that the level of the Index should rise and fall at double the rate of the reference index. The interest rate taken from the Index level is based on the rate at which banks in London lend US dollars to each other overnight. The reference index is designed to reflect the performance of shares of 500 companies representing all major US industries and comprises shares of large companies traded on the NYSE Euronext or the NASDAQ OMX markets. A company's weighting in the reference index depends on its relative size based on the combined value of a company's readily available shares compared to other companies on the stock markets. The Index is calculated on a total return net basis which means that all dividends and distributions by the companies are reinvested in the shares after tax.