The biggest change that has happened to the Sensex over these years is the prominence of the service sector, in line with what has happened in the economy as a whole.
The story behind the stocks that are dead is businesses that have perished owing to their inability to withstand competition post-liberalisation or managements that have failed to stand up to the challenges posed by the changing environment.
For instance, Century Textiles and Bombay Dyeing which were darling of the bourses some years ago were completely out of favour as their business dynamics changed and made them uncompetitive. Now, however, some of them are back in the limelight, as they are now set to capitalise on their most precious asset - mill land.
Ramdeo Agrawal, managing director, Motilal Oswal, said, "If the tailwind is strong, the management needs not do anything and the company will do will. But if the business goes for a toss the management can do little to pull it out."
Having said that, Agrawal also pointed out that some companies have perished as managements got into unrelated diversification (one example is Ceat) and lost track of their main business.
Stocks that have completely gone into oblivion are Asian Cable and Industries, Bombay Burmah Trading, Industrial Organics, Scindia Steam and Zenith Birla. Hindustan Motors, Ceat and Mukand are seriously ailing.
Conspicuous by absence in the original Sensex are stocks belonging to the new economy business and services space. Notably, baring Indian Hotels, there was not a single stock that operated in the services space when the index was first constituted. The Sensex did not feature even a single bank.
Currently, the services sector constitutes a significant chunk of the index with stocks such as Infosys, Wipro, HDFC Bank, HDFC, ICICI Bank and Bharti, dominating the index.
The three business groups, which have withstood the test of time are Reliance, the Tatas and the Birlas. Reliance, of course, has been a success story in the Indian corporate history growing in less than three decades to become the largest private sector enterprises in the country.
From the A V Birla group, Grasim, Hindalco and Indian Rayon figured in the original Sensex. The former two are still in the benchmark while the latter (now A V Nuvo) is a much sought-after stock, after several rounds of re-jigging which can completely transformed the character of the company.
The Tatas have done even better. The three stocks from the Tata stable Tata Motors, Tata Steel and Tata Power still find their place of pride in the table. Now, the most profitable business from the empire Tata Consultancy Services has also created space for itself.
Even in the pharma space, GlaxoSmithKline Pharma which figured in the Sensex earlier has been a steady performer.
It has survived through the toughest times when the country did not respect patents and now that the patent law is in place it is touted to be one of the best bets in the pharma sector.