Japanese refiner Idemitsu Kosan Co. Ltd. said Oct. 16 it has completed a deal to acquire Showa Shell Sekiyu K.K. through a share swap deal worth more than an estimated ¥600 billion.

Idemitsu will acquire the approximate 69% of Showa Shell shares that it does not already own. The companies would exchange 0.41 Idemitsu share for each Showa Shell share. Showa Shell shares will be delisted on or around March 27, 2019.

Once the combination is complete on April 1, 2019, the new company will work to maximize synergies of about ¥60 billion by 2021 as it revamps its business portfolio, while promoting environmental, social and governance initiatives.

The merger had been stalled for some time due to opposition from the founders of Idemitsu. In July, the two companies announced a deal to merge under which the founding family will be able to nominate two board of directors of the combined company, which will conduct business under the name Idemitsu Showa Shell.

Idemitsu head Shunichi Kito will serve as CEO of the new combined company.

Idemitsu said it still intends to buy back its own shares through December of this year to return profits to current shareholders.

Stock shares in Showa Shell and Idemitsu closed down 2.6% and 3.2%, respectively, on Oct. 16 following news of the definitive deal.

As of Oct. 15, US$1 was equivalent to ¥111.89.