At the resplendent China World Hotel in Beijing, scores of cameras snapped as colorful confetti floated down from the ceiling. It was Aug. 11, 2005, and this was the global coming-out party for Alibaba, the Chinese e-commerce upstart. After months of frantic negotiations, the American Internet giant Yahoo had agreed to invest $1 billion in cash and create deeper business ties, in exchange for a 40 percent stake in Alibaba.

Alibaba’s founder, Jack Ma, thin, energetic and standing just over five feet tall, was beaming. He gushed that it was China’s Valentine’s Day and this was a beautiful match: “You’d be foolish if you said no.” It was his coming-out party too; the partnership would pave the way for Alibaba to become an international juggernaut.

For days, Mr. Ma was almost giddy about a deal that provided his company with a huge infusion of money and unfettered access to Yahoo’s search technology. He was particularly effusive that eBay and Meg Whitman, who was then its chief executive, had enticed Yahoo to make a competing offer by bidding so aggressively for Alibaba. “Thank you, Meg Whitman,” Mr. Ma joked at the time. “Thank you for making all of this possible.”

But Mr. Ma soon started having second thoughts about the partnership. He worried that he had sold the stake too cheaply and given up too much control.

Trying to buy back most, if not all, of Alibaba’s shares, Mr. Ma started talks that dragged on for several years. With the relationship souring, Mr. Ma transferred ownership of Alibaba’s fast-growing online payment service, Alipay, to an entity that he controlled. He didn’t get the permission of Alibaba’s board. He just went ahead and did it.

While Yahoo complained, Mr. Ma seemed to get everything he wanted, eventually. In 2011, he negotiated an agreement giving him and a handful of key lieutenants a majority stake in Alipay, one of the company’s crown jewels. A year later, Mr. Ma secured a plan for Yahoo to reduce its stake in Alibaba.

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What Is Alibaba?

What Is Alibaba?

The e-commerce company has seized investor and public interest to an extent that is unusual for a company that does much of its business in China.

When the Alibaba Group goes public later this month in an offering that could value the company at about $160 billion, investors will have little doubt about who is in control of the company. Mr. Ma, 49, is the public face. He is the chief negotiator. He is the top strategist. He is the biggest individual investor, with a 9 percent stake.