NEW YORK (AP) — Amazon and eBay should watch their backs. As Chinese e-commerce powerhouse Alibaba readies what could be the biggest initial public offering ever on the New York Stock Exchange, it is quietly hinting at plans to expand into the U.S. The company controls nearly 80 percent of all e-commerce in China, and founder and chairman Jack Ma has ambitions that go beyond the country's borders. Earlier this week, at a Hong Kong stop on Alibaba's global tour to meet with potential investors, Ma surprised a pack of reporters, camped out in the lobby of the Ritz-Carlton hotel in Kowloon, with the clearest indication yet of his vision for growth. "Speaking for Alibaba, we hope to become a global company, so after we go public in the U.S.