* CSI300 up 1.29 percent to 2,534.4 points
* SSEC up 1.18 percent to 2,446.6 points
* HSI up 1.65 pct to 23,939.7 points
By Pete Sweeney
SHANGHAI, Nov 10 (Reuters) - China stocks rose by midday on Monday after Chinese and Hong Kong regulators formally announced a launch date for the long-awaited Hong Kong-Shanghai stock market connector scheme.
That has added momentum to a rally on China's stock exchanges, once among the world's worst-performing since the global financial crisis.
The Shanghai Stock Exchange main index is up nearly 15 percent year-to-day, now outperforming the S&P 500 index by nearly five percentage points over the same time period, after spending years in the basement.
The CSI300 index rose 32.25 points, or 1.29 percent, to 2,534.4 at the end of the morning session, while the Shanghai Composite Index gained 28.44 points, or 1.18 percent, to 2,446.6. The Hang Seng index added 387.24 points, or 1.64 percent, to 23,939.7.
Some mainland investors appeared to have positioned themselves well for the launch of the programme, despite reports that the progress was held up by concerns over democracy protests in Hong Kong, or alternatively technical challenges.
"Investors were interested in financial stocks because they believed the connector would be launched soon, and also because financials have had such cheap valuations," said Xiao Shijun, analyst at Guodu Securities in Beijing, referring to the fact that many Chinese banks have been trading at or near book value for years, to the frustration of regulators.
But in late October, mainland punters including institutional investors began moving into neglected blue-chip stocks eligible for purchase by Hong Kong investors.
As a result, the CSI300 Financial Services Index , dominated by banks and also by brokerages expected to benefit strongly from the connector scheme, rose more than 10 percent in the last 10 trading days, outperforming the wider market. The focus on those shares appeared to cannibalise interest from the NASDAQ-like ChiNext growth board, which has underperformed.
That caused the long-standing valuation differential between firms with dual listings in Hong Kong and Shanghai to finally evaporate on Monday.
Trading volumes on mainland indexes hit an all-time high on Oct. 31, and volumes have remained strong since. (Editing by Jacqueline Wong)