Jay Y Lee has been in detention since February and on trial for charges, including bribery and embezzlement as part of a scandal that led to the ouster of former president Park Geun-hye.
South Korean prosecutors on Monday sought a 12-year jail term for Samsung Electronics Vice Chairman Jay Y Lee, over charges including allegedly bribing ex-president Park Geun-hye for government support to cement Lee's control of Samsung Group.
Lee, 49, has been in detention since February. He is on trial for charges which include bribery and embezzlement as part of a scandal that led to Park's ouster.
Lee has denied wrongdoing.
Lee and four other executives are accused of bribing Park's powerful confidante with millions of dollars to win presidential favours and ease a controversial 2015 merger deal.
"The defendants were closely tied to power and sought personal gains," the prosecutors said.
They sought a 12-year sentence for Lee and terms ranging from seven to 10 years for three of his co-accused.
Lee has effectively been at helm of the vast Samsung group, the world's biggest smartphone maker and a sprawling business empire, since his father suffered a heart attack in 2014.
Taking the stand for the first time in his defence last week, Lee claimed that he had no role in decision-making at the wider Samsung group and "mostly listened to other executives."
His lawyers say the allegations were unjustified and the defendants never sought anything in return for the money that was donated.
The lower court ruling is expected by August 27, when Lee's current detention period ends.