Saudi Telecom Company (STC) will buy a further 25.8 percent of Viva for SR1.59 billion ($424 million), taking majority control of its affiliate following the close of a voluntary tender offer period for the Kuwaiti firm's shares.

This will raise STC's stake in Viva to 51.8 percent, the Saudi firm said in a bourse statement on Monday. The former monopoly currently owns 26 percent of Viva, which rapidly won market share after launching services in 2008 and turned profitable four years later.

STC in December said it would offer KD1 ($3.30) per share for all shares in Viva it did not own, a proposal Viva's board described as unfair.

Viva's shares had hit a record high of KD1.1 before STC revealed its offer price, but Gulf stock markets have since slid following a renewed slump in oil prices. Viva's shares ended Sunday at KD0.940.

Kuwaiti state institutions own about 16 percent of Viva, Reuters data shows. - Reuters