BlackRock has for the first time backed the inclusion of mainland Chinese shares in MSCI’s global indices, bolstering the index provider’s fourth attempt to have A-shares included in its benchmarks.

China hosts the world’s second-largest stock market and the third-largest bond market, but fund managers have argued over whether, and how, to include mainland assets in global indices — a move that would force index tracking funds to invest onshore.

An estimated $1.5tn follows MSCI’s flagship emerging markets stock index. Last month the index provider put forward a proposal for including A-shares that focused only on large-cap stocks available through the Stock Connect system, which allows international investors to trade stocks in Shanghai and Shenzhen through Hong Kong without having to register onshore.