Hong Kong's stock market is set to welcome a pair of big new listings this week, but the overall investor mood is likely to remain cool until the United States and China stop fighting over trade.

The benchmark Hang Seng Index on Wednesday will see the start of trading for mainland Chinese telecommunications infrastructure giant China Tower and Nasdaq-listed biotech company BeiGene.

The former is the world's biggest initial public offering in two years at $6.9 billion, according to Reuters, while cancer drug developer BeiGene is the first Nasdaq-listed biotech company to offer a secondary share flotation in Hong Kong.

The listings follow Chinese smart phone manufacturer Xiaomi's high-profile debut last month in what had been touted as a big year for initial public offerings in the semi-autonomous Chinese territory. But the highly anticipated new blood has failed to boost the Hang Seng, which is down about 8 percent so far this year.

Neighboring Chinese stock markets have also taken a big hit this year, weighed down by a slowing growth outlook, a weakening currency, U.S. President Donald Trump's trade offensive against Beijing, and China's retaliatory measures.

Stefan Hofer, chief investment strategist at LGT Bank in Hong Kong, said the local market has underperformed despite the city's solid economic and fiscal policy fundamentals.

The problem, he stressed, is elsewhere and out of Hong Kong's control.

"We do have this dark cloud from trade and that is casting a very long shadow over everybody," Hofer told CNBC. "And it's not that the Hong Kong market can completely escape that."

Hong Kong is considered a separate entity from China in terms of local governance and trade, so the territory is not subject to any new U.S. tariffs. But thousands of Hong Kong-owned companies have manufacturing operations in China and financial links with the mainland are growing.