Neither company was available for comment on Monday.

Brokerages are estimated to have spent at least HK$2 million each to upgrade their trading systems and hire staff in preparation for the link, according to Ronald Wan, chief China adviser at Asian Capital Holdings Ltd in Hong Kong.

Delays will also mean lost commissions from the net 23.5 billion yuan ($3.8 billion) of daily cross-border stock purchases allowed under the program.

"People will start to ask more questions after October. So long as they give a clearer indication, the market shouldn't have a problem, but if another week passes without any notice, participants will become more worried," said Jeffrey Chan, chairman of the Hong Kong Securities Association.

"Any reversal of market expectations may lead the market to a different direction, as the A-share market was growing based on a firm belief in the Stock Connect program," Hong Hao, chief strategist at BOCOM International Holdings Co Ltd, wrote in a note on Monday.

Analysts and investors hope Stock Connect will substantially improve market liquidity and lift sentiment.

But investors have become increasingly impatient since mid-October, when what was supposed to be a six-month preparation period ran out and authorities gave no indication for a possible start of the program. The benchmark Shanghai index sank 1.7 percent last week, the largest loss in four months.

"I do not think the rise of the A-share market since July has been supported by fundamentals. It was driven by other factors," said Wu Zhaoyin, an analyst with Shenzhen-based Essence Securities Co Ltd.

After all, statistics indicate that the macroeconomy is weak, the property sector is still struggling and tapering of quantitative easing in the United States is draining capital from global markets, Wu said. "We are concerned that the market will go through a correction in the fourth quarter."

The Hang Seng China AH Premium Index, which measures the weighted average gap between the largest dual-listed shares, dropped 2.7 percent last week, the most since March.

"Further delays will hurt investors who have been betting on the program, and brokers who have lost revenue opportunities," said Hong.

China's Top 10 stock market milestones	Stock Connect set to buoy use of more financial instruments