The Kwok brothers, joint chairmen of Sun Hung Kai Properties, were arrested by the Independent Commission against Corruption, the company said in a regulatory filing.
The New York Times reported Thursday that the brothers belong to a family worth about $18.3 billion, which put them at No. 27 on Forbes magazine's list of the richest people this year.
Details of the charges haven't been made public but the commission confirmed it had arrested two senior executives and one former official of the Hong Kong government. The charges are related bribery and "misconduct in public office," the Times reported.
The commission also said the case was connected to the arrests of Thomas Chan, a company director and four other people that occurred March 19.
Some observers said the case could be related to Walter Kwok, the third brother in the family, who ran the company until 2008, when a family dispute erupted, forcing Walter Kwok to leave the company that his father started in 1972.
"It looks like big brother got booted out of the company and he's now exacting his sweet revenge," said Francis Luen, of Hong Kong brokerage firm Lyncean.
"When there is a family feud, and it produces enough evidence to implicate them, it destroys the facade of harmony and family loyalty," Luen said.