Two major index providers took steps to increase the influence of mainland Chinese stocks in their widely tracked global benchmarks beginning next year — a vote of confidence in a market that has been battered by trade and economic concerns.

The actions by FTSE Russell and MSCI partly reflect how much easier it has become to buy and sell mainland stocks through a trading link with Hong Kong. The changes could also bring hundreds of smaller Chinese companies to the attention of international money managers for the first time.