Police said there was "no suspicious element" in the 15-year-old girl's fatal fall, but arrested both her parents on suspicion of "ill-treatment or neglect of a child or a young person".
Her father, 58-year-old Nick Cousins, is the managing director of the Hong Kong office of British multinational Jardine Lloyd Thompson (JLT), one of the world's leading insurance brokers.
The girl's mother is a 53-year-old Philippine national, the consulate in the Hong Kong said, adding that they were still ascertaining her identity.
The 15-year-old plunged from the 21-storey apartment block in Repulse Bay yesterday morning, police said.
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Her younger sister has been taken to a children's home, said welfare minister Matthew Cheung, who pledged his department would "provide whatever service required according to the welfare needs of the family".
He added that they are also seeking a protection order for the girl.
The teenager's mother has also been accused of overstaying her visa, while Cousins was accused of aiding or abetting the overstay. The couple were not married, Hong Kong police said.
"We are giving Nick our full support through this difficult time and he will be on extended compassionate leave until further notice," the statement said.
Police said that the teenager was pronounced dead at the scene after a security guard heard a loud noise and she was found lying on the ground.
"It was suspected that the subject fell from a height," police said without confirming which floor.
The South China Morning Post, citing a police source, said that the 15-year-old and her younger sister had been educated at a private tutorial centre and had never gone to school. Their births had also never been registered, the report said.