Oil refiner Eneos Holdings is considering selling as much as 70% of JX Advanced Metals in an initial share sale that may raise up to around ?700 billion ($4.5 billion), according to people familiar with the matter.

The Eneos board is set to discuss the IPO at a meeting on Friday, with Chief Executive Officer Tomohide Miyata favoring a sale of 50.1% while others involved in the decision-making process prefer 70%, said the two people, who asked not to be named because the deliberations aren¡¯t public.

There is a likelihood of Eneos settling on a number somewhere near the middle of the range, and there is no plan to issue new shares in JX, said the people. They added that the deliberations are ongoing, and details may still change.

Eneos shares briefly reversed losses in Tokyo trading following the report, before trading 1% lower at the lunchtime break in Tokyo. The benchmark Topix index slid about 0.5% in morning trading.

A representative of Eneos, which owns 100% of JX, said there is nothing to add beyond what has been previously said. Eneos revealed in October that it had applied to list JX on the Tokyo Stock Exchange. A representative of JX declined to comment.

It was reported in November that JX, which mines and refines metals, and also produces semiconductor materials, was looking to hire banks for an IPO and may seek a valuation for the whole company of ?700 billion to ?1 trillion.

While the prospect of Eneos offloading a majority stake in JX has been mooted for years, it is coming closer to reality amid a hot market for share sales in Tokyo.

Japan has seen the highest volume of IPOs this year since 2018, helped by a bullish equity market and a drive by the stock exchange to get companies to improve their value.

Eneos, the nation¡¯s biggest oil refiner, has said it would use funds raised through the stock sale for shareholder returns and investment in decarbonization.

JX generates about one-third of its operating income from the semiconductor materials sector, according to its website. Its customers include Applied Materials, the U.S. maker of chip-manufacturing equipment.