Alibaba raised its share buyback program to $25 billion on Tuesday, the largest ever repurchase plan by the e-commerce giant, to prop up its battered shares as it fights off regulatory scrutiny and concerns about slowing growth. Alibaba shares, which have more than halved in the past year, surged on the news and closed up 11 percent. Its U.S. listed stock rose 9 percent in premarket trading. This is the second time Alibaba Group Holding Ltd has expanded its buyback program in a year. It had hiked the program from $10 billion to $15 billion last August. “The upsized share buyback underscores our confidence in Alibaba’s long-term, sustainable growth potential and value creation,” Deputy Chief Financial Officer Toby Xu said. Alibaba said it had $75 billion in cash, cash equivalent, and short term investments as of end-December. The company has been under pressure since late 2020 when its billionaire founder, …