Bangkok Life Assurance (BLA) president Chone Sophonpanich will step down from the top post and all his other positions to spend more time with his family in the US.
His resignation will come into effect from July 1, the company said in a filing to the Stock Exchange of Thailand (SET).
Apart from his role as president, Mr Chone will give up all his other positions, including director, executive director and a member of the investment committee, the company said without commenting further.
Chone: Seeking more time with family in US
"The nomination and remuneration committee is in the process of selecting a new president and will notify the SET promptly," it said.
Mr Chone, 41, was appointed as BLA's president in February 2011. He started working at the company as a senior vice-president in 2008.
He is the son of Choedchu Sophonpanich, chairman of BLA and BBL Asset Management (BBLAM), and a grandson of Chin Sophonpanich, the founder of Bangkok Bank (BBL).
Mr Chone graduated with a master's degree in Economics and International Relations from Johns Hopkins University, and a Bachelor of Economics, upper second class honours, from University College London.
"For a year he told me that he wanted to spend his life with his family in the US. His resignation has nothing to do with business," said BBL Asset Management's chief executive Voravan Tarapoom, who is familiar with Mr Chone and works with Mr Choedchu.
She said that while Mr Choedchu would feel regret for his son's resignation due to his strong performance, he would accept it for the sake of his son's life.
Another source who commented on condition of anonymity reiterated that Mr Chone may go to the US after resigning, as his two children are set to study there.
BLA earlier said the company had set its first-year premium target this year at 22 billion baht, up 60% from last year, with a focus on health and pension insurance policies.
The company has just rolled out health insurance for diabetic patients.
It recorded a total premium of 44 billion baht in 2015, down 13% from the previous year, while its first-year premium rose 81%.
BLA reported a net loss of 6.89 billion baht for the first quarter of this year, compared with a net profit of 765 million over the same period last year.
BLA shares closed on the Stock Exchange of Thailand at 36.25 baht, up 25 satang in trade worth 46 million baht.