The battle for the world’s biggest mobile-payment market is turning cutthroat, says The Wall Street Journal. Since Chinese consumers began adopting mobile payment a few years ago, Internet giant Alibaba Group Holding Ltd. has had a lock on the market through its Alipay system. But now leading domestic rival Tencent Holdings Ltd. is leveraging the popularity of its WeChat social-messaging app to increase its slice, and big foreign players including Apple Inc. and Samsung Electronics Co. are jumping in with their own systems. Last year mobile transactions more than doubled to $235 billion, pushing China ahead of the U.S., where the market grew 42% to $231 billion. Tencent is spending heavily on discounts and distinct features, as well as making alliances to allow it to offer more on-demand services.