The regulatory storm that washed billions from Chinese corporate valuations in the name of curbing excesses exposes not only the policy risk under President Xi Jinping's increasingly activist tenure, but also the uncertainty over implementation.

Xi's campaign to clamp down on industries ranging from internet platforms and bitcoin to ride-hailing giant Didi Global and tutoring marks a historic shift as he prioritises broad-based prosperity over the all-out growth pursued for decades by China.

The furious pace of new rules and regulations, and the blunt and sometimes unpredictable force with which they are being implemented in the world's second-biggest economy...