Shares in Citic Securities, China's biggest listed brokerage, ended flat on their Hong Kong trading debut Thursday even as the broader market posted its strongest gain in two-and-a-half years.

Investors who subscribed to the firm's $1.7-billion share sale, one of the biggest this year, saw their stock close unchanged from its initial public offering (IPO) price of HK$13.30 ($1.71), after recovering earlier losses.

The stock fell to a low of HK$11.90, down more than 10 percent, at one point.

Citic's soft start on the Hong Kong stock exchange came as the Hang Seng Index ended up 5.67 percent, following several days of consecutive losses. The rise is the biggest since April 2009.

"As we know, many IPOs, not only in Hong Kong, but globally, have been postponed due to the market situation," K.C. Chan, the city's secretary for financial services and treasury said at the listing, according to a statement.

"Volatility is expected. This is not a kind of market where an IPO is easy to do," Chan added, lauding the firm -- which is already listed in Shanghai -- for going ahead with its Hong Kong debut despite market turmoil.

The brokerage locked in 50 percent of the offering from big-name cornerstone investors including Kuwait Investment Authority sovereign wealth fund and Singapore's state-owned Temasek Holdings.

The share sale was one of the world's largest this year, after Italian luxury goods maker Prada made a lacklustre debut in Hong Kong in June and raised a lower-than-expected $2.14 billion.

Several firms have recently backed off plans to list in Hong Kong, sparking concerns that the world's biggest IPO market may see delays in some $19 billion worth of share sales from a dozen companies.

Beijing Jingneng Clean Energy, a unit of the Beijing municipal government, has postponed its $630 million Hong Kong share sale.

Australian miner Resourcehouse also shelved an IPO originally slated to raise as much as $3.6 billion, citing weak market conditions.