The promoter group, which includes Adani Agro, Adani Commodities and some members of the Adani family, is selling 2.3 crore shares in AEL, the company said in a notice to the BSE.
The company had nearly 110 crore shares outstanding at the end of September.
The move comes after markets regulator Securities and Exchange Board of India (Sebi) set a deadline of June next year for all private sector listed companies to bring down their respective promoter shareholdings to 75% or lower.
Adani Agro is offering nearly 2 crore shares, with the rest being sold by Adani Commodities, and five members of the industrialist family.
The groups billionaire chairman Gautam Adani had recently said they were examining the possibility of raising $1.5 billion by reducing the promoters stakes in Adani Ports and holding company, AEL. Promoter shareholding is more than 75% in both the holding company and the ports business, which are listed on stock exchanges.
Gautam Adani had also said the group was considering issuing $1.5 billion in global bonds to raise funds to develop its flagship coal project in Australia. The group has invested $3 billion in the Galilee basin project in Queensland, where it is developing a coal mine as well as building rail and port infrastructure. It plans to invest another $7 billion over the next few years.
Heavy expenditure on the Australia project and losses in its India power business have raised questions about AELs debt burden. AEL has a debt to equity ratio of 2.9:1, but Adani has expressed hope that this will fall to a much more relaxed 1:1 ratio by 2015, as Indian authorities should raise power tariffs next year. AELs share closed up 3% at R291.60 on Wednesday on the BSE.