"There are 17 to 18 unlisted companies in the group. We will try to bring down the number to five," the B K Birla Group patriarch told PTI in a free-wheeling interview.
He said that process had been already started and legal formalities would have to be completed, but would take time.
These are all investment and trading companies, he said.
Although B K Babu, as he is fondly referred to by those who know him, plans to retire in three years when he turns 90, he said his wife Sarala and grandson Kumarmangalam Birla were unhappy with his decision to call it a day.
"She (Sarala) has not accepted the decision. I have told her that I have been going to office since the age of 17. Now I want to have a peaceful retired life," he said.
Sarala, who was by Birla's side, said: "I want him to continue in office as long his health permits." But Birla, who said he looks up to his wife for advice on every major issue, insisted he was keen on pursuing his passion for art and culture.
"She is the boss, not me," he quickly added.
Not only Sarala, Kumarmangalam too is not happy with Birla's decision to retire. B K Birla is currently the chairman of four companies, Kesoram Industries, Jayshree Tea, Century Textiles and Century Enka.
Kumarmangalam, who presides over the Rs 45,000 crore (Rs 450 billion) Aditya Birla Group, is set to receive the tyre and cement businesses of B K Birla Group's flagship
Kesoram Industries as per the succession plan. Besides, he would also get to manage Century Textiles and Century Enka.
The spun pipe unit of Kesoram would be inherited by his daughter Manjushree Khaitan, while Jayshree Tea would go to his other daughter Jayshree Mohta.
Saying he trusted none other than Kumarmangalam to run his key businesses, Birla said: "In my absence, the companies will have to be run efficiently. I want to work for the shareholders and not for the family."
Even after transition is over, the Kolkata-based industrialist said he would assist his daughters and grandchildren.
"Now I do from nine to four. But after 90 when I retire, I will go to office for two or three hours. I want to get relief from day-to-day affairs."
Birla, who will turn 87 in January, said that Kumarmangalam was free to do what he felt like with Kesoram after his lifetime. "During my time, I do not want Kumar to amalgamate the cement unit of Kesoram with either Ultratech or Grasim.
"But I know he would not do that. Kumar has the experience of running a huge empire (Aditya Birla group) independently and has no arrogance", Birla said.
Asked why Kumar was chosen to inherit so many companies, Birla said: "There is no alternative (person to take care of shareholders interest)".
In Kesoram Industries alone, there were over one lakh shareholders, he said, adding that it was a very big company.
While Birla was yet to decide on the succession plan for Mangalam Cement and ECE, Mangalam Timber would go to Vidula Jalan, daughter of Manjushree Khaitan.
He said that Manjushree Plantations would also go to Manjushree Khaitan.
