TAIPEI, Taiwan — It was the ultimate success story of China Inc 2.0: a private-sector technology startup became an Internet juggernaut that conquered the Chinese market and set its sights on the world.

But like in the folk tale, Alibaba first struck gold — and then met trouble.

Chinese regulators announced a multi-pronged antitrust investigation Thursday into its most successful Internet company, making moves that could potentially break up Alibaba’s sprawling e-commerce business or splinter its highly lucrative financial services affiliate.

While it has grown into the dominant player in Chinese online shopping — now raking in $50 billion a year in revenues — Alibaba in the last decade has steadily encroached on China’s tightly controlled financial sector through its Ant Group spin-off. Ant Group, a $16 billion-a-year business, has been chipping away at powerful state banks’ market share and unnerving regulators with investment and lending products that have become so popular that Ant sometimes acts as a lender to government banks — not the other way around.