Hyundai Rotem, the Hyundai Motor Group affiliate that builds South Korea's K2 battle tank, will buy the defense business of sister company Hyundai Wia for 358.4 billion won, The Herald Business and The Korea Times reported Monday.

The Herald Business put the price at about $267 million, while The Korea Times put it at $252 million. The two companies held board meetings Monday and signed the deal, according to their regulatory filings. It is set to close by March 31 next year.

The unit makes the main guns for the K2 tank and gun barrels for the K9 self-propelled howitzer, which is built by Hanwha Aerospace. Buying it lets Hyundai Rotem build both the tank and its main gun, which should cut costs and make its supply chain steadier, The Korea Times reported. With K2 exports growing, the Herald said, control over key parts matters more.

The unit's business was valued at 480 billion won, the Herald reported. The final price is lower because land and buildings worth 117 billion won are not part of the sale and will be leased instead. The deal covers the unit's operating assets, debts and employees who transfer. Last year the unit had sales of 393.1 billion won, or 4.6% of Hyundai Wia's revenue.

Hyundai Wia will hold a special shareholder meeting at its headquarters in Changwon on Nov. 27 to vote on the sale, the Herald reported. It plans to put the money into future businesses, including thermal management systems for electric vehicles and robotics.

The deal is part of a wider reshuffle in the group. In July, Hyundai Wia spun off its precision machinery business and sold it to a consortium led by Rylson Private Equity for 340 billion won, The Korea Times reported.

What we know: Hyundai Rotem agreed to buy the gun-making unit for 358.4 billion won, with closing set by March 31.
What we don't: Whether Hyundai Wia shareholders will approve the sale.