Mr. Cheung is also an independent non-executive director of insurer AIA Group Ltd.

WSJ: Hong Kong Mercantile Exchange Being Probed

No allegations of wrongdoing have been made against Mr. Cheung, who has chaired HKMEx since its founding in 2008.

WSJ: Hong Kong Mercantile Exchange Being Probed

Spokesmen for AIA and Rusal said Mr. Cheung's positions at the companies remained unchanged, and they declined to comment further.

WSJ: Hong Kong Mercantile Exchange Being Probed

Mr. Cheung took an immediate leave of absence Tuesday from public duties.

WSJ: Hong Kong Mercantile Exchange Being Probed

HKMEx's Mr. Cheung said they weren't employees of the exchange.

WSJ: Hong Kong Mercantile Exchange Being Probed

Kevin Morgan, Geovisions' chief executive, said the complaints are the first related to Mr. Cheung's company that he is aware of in at least four years of working with the franchisee.

WSJ: Guest Worker Visa Troubles Visit McDonald's

Kah Inn Lee, a 23-year-old student from Malaysia, said a curtain separated the men's and women's beds in the tiny basement she shared with seven other students in a house owned by Mr. Cheung's son.

WSJ: Guest Worker Visa Troubles Visit McDonald's