SHANGHAI, Sept 21 (Reuters) - China's Shenzhen Stock Exchange said on Saturday it would replace six companies in its 40-member blue chip composite index , the third time it has made an adjustment this year.
The exchange gave no explanation for the changes, which take effect on Monday and follow similar moves in January and May seen by analysts as a regular attempt to make the index more representative of the market.
Minivan and light truck maker Jiangling Motors Co is one of the six companies that will join the blue-chip index, the Shenzhen exchange said in a statement published in the official Securities Times.
The firm, in which U.S. auto giant Ford Motors has a 29.96 percent stake, reported an 85 percent year-on-year jump in first-half net profit and has listed both hard currency B shares, open to foreigners, and domestic-investors-only A shares.
Three major steel firms -- Beijing Shougang Co Ltd , Angang Newsteel Co Ltd and Bengang Steel Co Ltd -- will be added as well as two A share companies, the exchange said.
The six that were axed are also A shares, off limits to foreign investors.
The Shenzhen exchange made its first adjustment to the blue-chip index in December 1997, nearly three years after the index was launched in January 1995. The second adjustment was made in November 1999.
Since the start of this year, the exchange began to update the index once every four months after investors complained that it was not a good monitor for market heavyweights.
China's Shanghai Stock Exchange replaced its 30-member blue chip index with an 180-member index in July to better track large caps.
Analysts say they expect the Shenzhen exchange to launch a comparative 120-member index soon, which with the SSE180 will form the basis for a planned unified stock index to track companies on both exchanges.
China has about 1,200 listed companies with a combined market capitalisation of $500 billion, rivalling Hong Kong as Asia's second-largest market after Japan.
But two-thirds of this market are not free-floating and the bulk of the rest are off limits to foreign investors.