Codenamed "Fuse", the operation alleges that senior executives of two securities firms accepted bribes of over HK$4 million to disclose confidential information to a hedge fund management firm.

The hedge fund firm used tips about share placements of various listed companies before they were publicly available to make a profit of HK$315 million from its short positions, the two commissions said.

Six men and two women were arrested, including executives from both companies and a middleman, the Securities and Futures Commission (SFC) and the Independent Commission Against Corruption (ICAC) said in a joint statement.

"During the joint operation, officers of the ICAC and the SFC searched a total of 14 locations, including the offices of the licenced corporations, as well as residences of the arrestees," it added.

Chinese securities firm Guotai Junan International said in a filing to Hong Kong's stock exchange that an employee had been detained by officials from the two commissions after its office was searched.

Other involved firms include broker Citic Securities and investment firm Infini Capital Management, Bloomberg News reported, citing people familiar with the matter.

Hong Kong's market watchdogs conducted a similar operation in December 2017 and arrested three executives, months after the city saw a dramatic stock crash.