And there's one American company that will experience a windfall from Alibaba's stock, not just today, but in the months and years to come: Yahoo.
Yahoo's continued windfall would have been smaller if not for one woman at the company. Not CEO Marissa Mayer but chief development officer Jacqueline Reses.
Reses actually holds the unusual combination of two roles at Yahoo. As chief development officer, she heads up Yahoo's M&A strategy. She's also the head of Yahoo's HR department, which says a lot about how Yahoo thinks about hiring talent.
And today's history making day is such a big day for her, she admits to tears with Alibaba CEO Jack Ma, she tweeted.
The enormity of today is overwhelming. Cried at dinner with Jack. Wow. I am speechless.
- Jackie Reses (@jackiereses) September 19, 2014
Alibaba opened at $68 per share, raising $21.8 billion at a valuation of about $168 billion.
Yahoo will sell 121.7 million shares and put about $5.1 billion in cash into its coffers. And, thanks to Reses, Yahoo will hold onto another 401.8 million shares in Alibaba. The stock is up to $90 on its first day of trading, so Yahoo's take is worth $36.2 billion.
But it was a long, complicated and often ugly road that got Yahoo here.
At one time, Yahoo had a 43% stake in Alibaba, bought for $1 billion years ago by Yahoo co-founder and then CEO Jerry Yang.
In 2009, Yang's successor Carol Bartz notoriously blew up Yahoo's relationship with Alibaba. At her very first meeting with Ma, she reportedly dressed him down in front of his senior executive team, Forbes reported. And things devolved from there.
The negotiations between Yahoo and Alibaba about cashing out Yahoo's stake during this time were acrimonious, complicated and pretty much went nowhere.
In 2012, under then-CEO Scott Thompson, the two companies stitched together a deal: Yahoo agreed to sell back half its stake in the Chinese Web company for $7 billion, AllThingsD reported.
Then Thompson got caught up on a scandal over over a fake computer science degree on his resume and left Yahoo. The Alibaba deal closed under Mayer.
Yahoo was supposed to be on the hook to sell another 208 million shares, or 40% of its remaining stake in Alibaba in the IPO.
Enter Reses.
Shortly after Mayer took the helm, Mayer asked Rese to join Yahoo, luring her away from a career as a private equity investor for Apax Partners.
Reses became Yahoo's representative on Alibaba's board. Over months, she renegotiated a new deal for Yahoo that allowed Yahoo to keep more of its stake, selling 140 million shares in the IPO not 208 million, it said in July.
Retaining a bigger stake gives Mayer breathing room as turns Yahoo's around. It keeps investors happy with Yahoo's share of the fast-growing Alibaba.
Reses has the personality to work magic. She's smart, funny, likeable and irreverent.
In fact at the exact moment Yahoo was announcing the revised Alibaba deal, Reses was on stage cracking jokes at Fortune's Brainstorm conference in Aspen.
When asked if she thought competitor AOL would be acquired in the next two years, without missing a beat she quipped, "Not by us." That line quickly went viral on Twitter.
Reses is also tireless. She's completed more than 40 acquisitions for Yahoo in the past two years, slowing her pace down only to work on the Alibaba IPO, she said at the conference in July.
She's back on the acquisition horse. In August, Yahoo closed its deal to buy Flurry, in a deal said to be valued at over $200 million, the Wall Street Journal reported.