July 10 (Reuters) - China's Ant Group has announced a surprise share buyback that values the fintech giant at $78.5 billion, well below the $315 billion touted in an abandoned IPO in 2020, in a move that may let some investors exit. The announcement came after China's financial regulator on Friday fined the Alibaba Group (9988.HK) affiliate $984 million for violating laws and regulations, a move seen by many industry observers as a sign that a regulatory crackdown on the country's technology sector is over. Here is what people are saying about the news: GARY NG, ASIA PACIFIC SENIOR ECONOMIST...