Alibaba and Tencent Face End of an Era as Sales Start to Shrink

For almost a decade, Alibaba Group Holding Ltd. and Tencent Holdings Ltd. embodied China’s economic miracle, sustaining a dizzying pace of growth and approaching trillion-dollar valuations with splashy forays into every corner of the internet.

That spectacular run could officially end Thursday, when the e-commerce powerhouse that Jack Ma founded is expected to record its first-ever decline in quarterly revenue — one of the few major Chinese internet corporations to do so, ever. Fellow billionaire Pony Ma’s Tencent, the social media powerhouse, could follow suit days later.