Hong Kong’s financial regulators and anti-graft agency arrested eight people this week as part of an investigation into a HK$315 million ($40 million) insider dealing and corruption scheme involving two major brokerages and a hedge fund manager.

The joint operation, codenamed “Fuse”, targeted senior executives suspected of exchanging confidential information for bribes, according to a statement from the Securities and Futures Commission and the Independent Commission Against Corruption.

While the official statement didn’t name the entities, people familiar with the matter said the local offices of Citic Securities Co and Guotai Junan International Holdings Ltd were among those raided. Infini Capital Management Ltd, an investment firm founded by Tony Chin, was also caught up in the sweep, according to the people, who asked not to be identified discussing a private investigation.

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The investigation centers on allegations that executives at the securities firms accepted more than HK$4 million in bribes from a hedge fund manager. In exchange, they allegedly leaked non-public details regarding share placements for several Hong Kong-listed companies.