Elsewhere, in recent months Alibaba has struck deals to buy full control of AutoNavi, a Chinese mapping service listed in the United States, and a 50 percent stake in one of China's top soccer teams. According to some reports — and distressingly to some potential investors — Alibaba co-founder Jack Ma decided to buy the stake in Guangzhou Evergrande in about 15 minutes after having had drinks with the club's owner.
Alibaba's investment plan is not aimed at directly competing with established American Internet heavyweights like Amazon and eBay, however. In its I.P.O. prospectus, Alibaba says that its investments will remain focused on China, where the company still sees enormous growth potential.
For the American start-ups in Alibaba's embrace, there are benefits beyond the investment. Kabam, for instance, receives a direct line into China, one of the fastest growing smartphone and gaming markets of the past decade. Some 40 percent of global smartphone shipments in the first quarter of 2014 were bound for Chinese consumers, according to IDC, a research firm.
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It is not, however, a simple market for a Western company to enter. Alibaba's knowledge of China's web-connected consumers could help American start-ups navigate the unfamiliar landscape.
"Entering Asia is very complex," said Kent Wakeford, chief operating officer of Kabam. "There are different payments systems, different types of phones and tablets to deal with. Even the culturalization is different."
Mr. Zeisser and his team have spent significant amounts of time helping their newfound partners, executives at the portfolio companies have said, advising on strategies and helping solve problems.
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"They've been quite active and contribute significantly on our strategy," Mr. Setton of Tango said. "They have also given us the financial chops to be able to do things we wouldn't have been able to do before."
—By The New York Times' Mike Isaac and Michael J. de la Merced