Hang Seng adopts sweeping changes to Hong Kong stock benchmark

The number of constituents in the Hang Seng index will increase from 52 to 55 starting from 15 March and ultimately fix at 100 eventually

The index constituents are expected to gradually increase to 80 through regular reviews by mid-2022 and be fixed at 100 ultimately.
Other changes that will be adopted, via Bloomberg:

 

HSI
The 8% weightage cap will lessen the impact of Tencent and HSBC slightly but those two are likely to still be the dominant shares in the index for a while.