PING An Insurance (Group) Co, China mainland's second-biggest insurer, may join Hong Kong's Hang Seng Index after a quarterly review of the stock benchmark, according to Nomura Holdings Inc and Core Pacific-Yamaichi International (HK) Ltd.

China Overseas Land & Investment Ltd, a Hong Kong-based developer controlled by the construction ministry, also may be added, said Kent Yau, deputy head of research at Core Pacific-Yamaichi in Hong Kong.

HSI Services Ltd, which compiles Hong Kong's stock indexes, will announce the changes on Friday, according to its Website.

The addition of companies incorporated in the mainland, known as H shares, reflects their growing importance in Hong Kong, Bloomberg News reported.

H shares at the end of March accounted for 23 percent of the value of the Hong Kong stock exchange's main board, up from 1.5 percent at the end of 1997, the exchange's Website shows.

"We've been seeing H shares becoming increasingly important in recent years, both in terms of their market cap and turnover," Sandy Lee, a Hong Kong-based analyst at Nomura, said in a phone interview. "This trend is bound to continue."

Changes to the Hang Seng Index will prompt funds that mirror the benchmark, such as the HK$26.21 billion (US$3.35 billion) Tracker Fund of Hong Kong, to adjust their holdings. So far five Chinese mainland stocks have been added to the Hang Seng.