Hyundai Motor Co's chairman and vice chairman are seeking to raise about $1.25 billion by selling shares of Hyundai Glovis, a person familiar with the matter said, a move that could smooth succession in the family-owned conglomerate.

The sale could help vice chairman and heir apparent Chung Eui-sun buy stakes in key units such as Hyundai Motor, Kia Motors Corp and Hyundai Mobis Co Ltd, without subjecting Hyundai Glovis to antitrust regulations governing inter-affiliate transactions, company watchers said.

"The Hyundai Glovis stake is the most important asset for Chung Eui-sun. Any sale would accelerate Hyundai's succession," said Kim Sang-jo, head of shareholder activist group Solidarity for Economic Reform.

Hyundai Motor Chairman Chung Mong-koo plans to sell some 1.8 million shares of Hyundai Glovis. Only son Eui-sun, Hyundai Glovis' biggest shareholder, is seeking to sell 3.2 million shares, said the person, who was not authorized to speak publicly on the matter and so declined to be identified.

After the sale, Eui-sun would hold 23.3 percent of Hyundai Glovis, and Mong-koo's stake would shrink to 6.7 percent.

On Tuesday, Hyundai Glovis will offer shares in the range of 264,000 won to 277,500 won ($244 to $256) each, a discount of up to 12 percent to their last closing price, the person said.

A spokesman at Hyundai Glovis declined to comment.