Where have you noticed the decline of interest in shareholding patterns? Literature or is it India specific? Also, is it for IPOs or in general?

Dear colleague, I recently read an article by Franks & Mayer of 2017: "Evolution of ownership and Control around the world: the changing face of capitalism". I find it interesting since it carries out an evolutionary study of the last hundred years of the ownership structure and the functioning of the markets, I hope it can help you in your research work.

Dear Baba

Some other related lines of thought to your query are:

Distinguishing voting (control) and nonvoting (superior return) shares. See https://academic.oup.com/rfs/article/7/1/125/1568365

Corporate governance (control) affected by government regulation and culture. See Article The Corporate Governance Behavior and Market Value of Russian Firms

The objective of stock repurchases (reducing market capitalization) is earnings management. See Article Stock Repurchases as an Earnings Management Device

dear prof. Baba Gnanakumar

we can understand the selling the owner's share in equity in this way.

owner's, who are usually entrepreneurs, are risk seeking people and they stay with the firm till it reaches the maturity stage( i.e, its market share is saturated). when a firm reaches it s maturity stage, its growth rate slows down remarkably and so, there will be no remarkable rise in the stock price. At this point of time, owners sell way their shares and realize maximum possible capital gain and they enter into other entrepreneurial activity.

any further discussion in this regard is most welcome.

I haven't come across with such research on related topic but for more help to accomplish your task please pass through FII Ownership in Indian Equity Securities you may find something helpful to you.