HONG Kong Exchanges & Clearing Ltd’s websites suffered cyberattacks on Thursday, though they were unrelated to the afternoon’s derivatives market trading halt, according to its chief executive officer.

Charles Li said that the company has seen distributed denial-of-service attacks against its websites many times this year. The derivatives problem was a software bug in a system provided by a vendor, he said, without giving more details.

HKEX’s troubles on Thursday came around the time that Hong Kong Chief Executive Carrie Lam was discussing the city’s unrest. The halt means that some traders are facing losses, said Louis Tse, Hong Kong-based managing director at VC Asset Management Ltd.