China Securities Index Co., Ltd. recently announced the periodic rebalancing of several major indexes, including the CSI 300, CSI 500, CSI 1000, CSI A50, CSI A100, and CSI A500. The adjustments will take effect after the market closes on December 12.

Following index rules and expert committee reviews, the CSI 300 will replace 11 constituents, adding stocks such as Huadian New Energy (600930.SH) and Dongshan Precision (002384.SZ). The CSI 500 will replace 50 constituents, including Hefei Chipmore Technology (002402.SZ) and Hua Hong Semiconductor (688347.SH). The CSI 1000 will refresh 100 constituents, with newcomers like Shijia Photonics (688313.SH) and Yongding Co. (600105.SH). The CSI A50 will update 4 constituents, such as InnoLight Technology (300308.SZ) and Huagong Tech (000988.SZ). The CSI A100 will adjust 6 constituents, including East Money (300059.SZ) and Sugon (603019.SH), while the CSI A500 will replace 20 constituents, adding firms like Guotai Junan Securities (601211.SH) and VeriSilicon (688521.SH). Other indexes will also undergo corresponding adjustments.

Post-rebalancing, sectors like information technology, communication services, and industrials see increased representation and weightings. The A-series indexes now exhibit more balanced industry allocations compared to traditional broad-based indexes, further elevating their "new quality productivity" focus—aligning with national strategic goals and resource allocation guidance.

Key changes include: - **CSI 300**: IT and communication services gain 4 and 2 constituents, with weightings up 1.46% and 0.75%, respectively. - **CSI 500**: Industrials add 11 constituents, lifting the sector’s weight by 2.48%. - **CSI 1000**: Communication services and industrials rise by 6 and 2 constituents, with weights increasing 0.44% and 0.37%.

Notably, STAR Market and ChiNext constituents grow by 3, 6, and 9 across these indexes, with combined weights reaching 21.26%, 28.07%, and 36.16%, reinforcing their innovation-driven profiles.

The A-series indexes emphasize equilibrium amid market shifts. The CSI A50, A100, and A500 show prominent IT and communication services weighting gains, while financials decline post-adjustment. Emerging industries now account for 51.23% of the CSI A500, up 0.79%.

Coverage metrics: - **Market Cap**: CSI 300, CSI 500, and CSI 1000 cover 51.92%, 14.83%, and 13.22% of total A-share market cap, respectively. The A-series indexes cover 15.31% (CSI A50), 26.37% (CSI A100), and 52.58% (CSI A500). - **Fundamentals (Q3 2025)**: - Revenue shares: CSI 300 (59.68% of A-shares), CSI 500 (15.13%), CSI 1000 (11.83%). - Net profit shares: CSI 300 (81.81%), CSI 500 (9.70%), CSI 1000 (6.12%). - A-series indexes: CSI A50 (18.26% revenue, 19.75% profit), CSI A100 (32.50%, 33.02%), CSI A500 (61.82%, 68.16%).