Chinese authorities are investigating the 2016 merger of ride-hailing giant Didi Chuxing Technology Co. with the China unit of Uber Technologies Inc. The deal created an industry behemoth that controls more than 90% of the Chinese market.

Wu Zhenguo, head of the Anti-Monopoly Bureau of the State Administration for Market Regulation, told media Friday that regulators are still assessing the deal under anti-monopoly law.

The $35 billion combination raised monopoly concerns from the very beginning, and officials on several occasions have pledged to review its impact on the market.

Analysts said the slow anti-trust review reflects the complexity and technical nature of the new ride-hailing market, which mean it will take time to evaluate market changes.