Tse Man- lai, 28-year-old businessman, launched denial-of-service (DoS) attacks on Hong Kong stock exchange last year. The seven companies, which included HSBC, Cathay Pacific Airways and HKEx itself, had a combined market value of HK$1.5 trillion. Trading in the shares of seven companies was suspended, as the companies had tried to make price-sensitive announcements during the lunchtime trading break, which investors might not have seen because of the website’s crash.
Source: https://thehackernews.com/2012/11/hong-kong-stock-exchange-hacker.html