Shares in Samsung Electronics and affiliates rose on Monday after the death a day earlier of Chairman Lee Kun-hee sparked hopes for restructuring and stake sales, analysts said.
Investors were betting that such measures would be needed to pay a hefty inheritance tax, estimated around 10 trillion won ($8.9 billion) for stock holdings alone, although analysts were divided on which moves were most likely.
Shares in Samsung C&T and Samsung Life Insurance rose as much as 21.2% and 15.7% respectively, while shares inSamsung BioLogics, Samsung SDS and Samsung Engineering also rose.
"The inheritance tax is outrageous, so family members might have no choice but to sell stakes in some non-core firms" such as Samsung Life, said NH Investment Securities analyst Kim Dong-yang.
Investors have long anticipated a shake-up in the event of Lee's death, hoping for gains from any restructuring to strengthen de facto holding company Samsung C&T's control of crown jewel Samsung Electronics, such as Samsung C&T buying an affiliate's stake in the tech giant.
Son and heir apparent Jay Y Lee has a 17.3% stake in Samsung C&T, which owns a 5.01% stake in Samsung Electronics, the global leader in smartphones and memory chips. Samsung C&T also has a 19.3% stake in Samsung Life, the No.2 shareholder of Samsung Electronics.
"At this point, it is difficult to expect when Samsung Group will kick off with a restructuring process as Jay Y Lee is still facing trials, making it difficult for the group's management to begin organisational changes," KB Securities analyst Jeong Dong-ik said.
Lee is undergoing two separate trials over suspected accounting fraud and stock price manipulation connected to a 2015 merger, and concerning his role in a bribery scandal that triggered the impeachment of former South Korean President Park Geun-hye.
His father Lee was the wealthiest stock owner in South Korea, with holdings including 4.18% of Samsung Electronics common shares and 0.08% of preferred shares, worth about 15 trillion won ($13.3 billion) in total.
He also held a 20.76% stake in Samsung Life worth about 2.6 trillion won, and a 2.88% stake in Samsung C&T worth about 564 billion won as of Friday's closing.
(Reporting by Joyce Lee and Hyunjoo Jin; Additional reporting by Heekyong Yang; Editing by Stephen Coates)