All BSE indices reflects the growth in market value of constituent stocks over the base period in Rupee terms. A need was felt to design a yardstick by which these growth values are also measured in Dollar terms. Such an index would reflect, in one value, the changes in both the stock prices and the foreign exchange variation.

This was facilitated by the introduction of a dollar-linked index in which the formula for calculation of index is suitably modified to express the current and base market values in dollar terms. The scope for dollar-linked index emerged from the background of Indian equity markets increasingly getting integrated with global capital markets and the need to assess the market movements in terms of international benchmarks. The dollar-linked indices are useful to overseas investors, as it helps them measure their 'real returns' after providing for exchange rate fluctuations.

Dollex-30, a dollar-linked version of SENSEX, was launched on July 25, 2001 whereas Dollex-200, a dollar-linked version of BSE-200 was launched on May 27, 1994. These indices were initially calculated at the end of the trading session by taking into consideration day's rupee/ US$ reference rate as announced by India 's Central Bank i.e. Reserve Bank of India.

BSE introduced Dollex-100, a dollar linked version of BSE-100, on May 22, 2006.

Dollex-30, Dollex-100 and Dollex-200 are calculated and displayed through BSE On-line trading terminals (BOLT) by taking into account real-time Re./US$ Exchange rate. The formula for calculating the index is:

Dollex =	Index Value (In local currency) * Base rupee-US$ rate
	Current rupee-US$ rate