Hang Seng Indexes Co added biopharmaceutical company Innovent Biologics Inc to its stock benchmark in the Hong Kong Special Administrative Region, the index compiler said following its quarterly review.

The rebalance brings the number of constituents on the Hang Seng Index to 89 from 88, according to a statement on Friday. The changes will take effect on Dec 8.

The review is closely watched as a sign of which listed companies are excelling across key metrics, such as market capitalization and turnover. Inclusion can also attract investments from index-tracking funds. The Hang Seng Index has gained 26 percent so far in 2025, poised for its strongest gain in eight years.

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Meanwhile, Innovent Biologics, Yum China Holdings Inc and China Hongqiao Group Ltd will join the Hang Seng China Enterprises Index, a gauge of Chinese mainland companies listed in the HKSAR. Haidilao International Holding Ltd, ENN Energy Holdings Ltd and New Oriental Education & Technology Group Inc will be removed from the index. Its total number of members will remain at 50, the index compiler said.