The stock closed at $44.90 on its first day of trading, giving Twitter a value of more than $31 billion based on its outstanding stock, options and restricted stock that'll be available after the IPO. It opened at $45.10 and traded as high as $50.09 in the morning. Although the closing price fell 20 cents short of the opening price, it's still 73 percent above the $26 IPO price. 5 p.m.: Big payday for @Twitter co-founders @Jack, @ev and CEO @dickc At the closing price of $44.90, Evan Williams' stake in the company is worth $2.6 billion. He emerged as Twitter's largest shareholder when he bought the service for an undisclosed amount through a company called Obvious, which he owns. Jack Dorsey, currently its chairman, has a stake worth $1.05 billion. Dick Costolo, who became CEO in 2010 and groomed the company for its stock debut, owns a stake worth $345 million. 4:55 p.m.: Sure, @Twitter had strong #IPO, but what exactly is it? AP's Scott Mayerowitz @GlobeTrotScott explains: http://bit.ly/HIKnsc 4:45 p.m.: Even with first day of trading finished, there's debate over @Twitter start. #ecstasy&agony Twitter's stock market debut represents another moment of glory for Chairman Jack Dorsey and a cruel reminder of what might have been for its exiled co-founder, Noah Glass. The former colleagues have vastly different accounts about how Twitter got its start. Dorsey says he conceived the concept for Twitter on a San Francisco playground, drawing upon his fascination with dispatch systems for taxis, bike messengers and emergency services. Glass credits Dorsey with having a vague idea about how to share status, but asserts it didn't turn into Twitter until the two of them spent several hours bantering in a car on the rain-slickened streets of San Francisco after a night of drinking. Glass was never given any credit in the documents leading up to Twitter's IPO, perhaps because he didn't end up staying at the company for very long. He was forced out well before Twitter began to gain mainstream appeal in a coup detailed in a new book about the company. He wasn't at Thursday's debut on the New York Stock Exchange. Dorsey, 36, doesn't come off well in the book, but he can still find solace in the wealth that he will reap from Twitter's success. He has a 4.3 percent stake in the company. Glass, 43, apparently left Twitter with little, if any, stock. He now lives with his 7-month-old daughter and the baby's mother in a small San Francisco house located about a half-mile away from the intersection where he says he hatched Twitter with Dorsey on a drunken evening nearly eight years ago. That memory still lives on the Internet at http://bit.ly/fMY6sx . His home on Thursday: http://pic.twitter.com/2DduLFRbNZ Read more: http://bigstory.ap.org/article/founders-differ-tale-twitters-creation 4:25 p.m.: @Twitter stock debuts strong, even as @AP @CNBC poll released earlier showed skepticism. Twitter's stock had a strong first-day showing. It's worth noting that it faced skepticism from potential investors and the broader public leading to Thursday's debut. According to an Associated Press-CNBC poll released Monday, some 36 percent of Americans say buying stock in the 7-year-old company would be a good investment, while 47 percent disagree. That said, 64 percent of the people polled said they don't own stocks, bonds or mutual funds at all. Read more: http://bigstory.ap.org/article/ap-cnbc-poll-twitter-faces-skeptical-investors 4:15 p.m.: AP's @liedtkesfc posts photo from Twitter co-founder @noah Glass' home: pic.twitter.com/2DduLFRbNZ 4:10 p.m.: $TWTR's closing price of $44.90 gives Twitter a value of more than $31 billion. It's actually 20 cents lower than the opening price, but still 73 percent higher than the $26 IPO price. RT @KenSweet: One way to read this: If you bought Twitter at its first trade of $45.10, you lost (a little) money today. $TWTR 4 p.m.: First day of trading is done. Twitter soars about 73 percent from IPO price, keeping most of gain from opening. 3:55 p.m.: As Twitter's first trading day nears an end, keep in mind at least one analyst believes $twtr is now a "Sell." Pivotal Research Group analyst Brian Wieser slashed his rating on Twitter Inc. from "Buy" on Thursday after the stock opened at $45.10, about 50 percent above his price target of $30. His price target valued the company at 21 times its free cash flow in 2018, a multiple that exceeded even Facebook at 17 times and Google at 16 times. With a stock price of $45, Twitter would be worth 32 times its 2018 free cash flow, which he wrote in a research note was "overly optimistic." Wieser told AP's @BarbaraOrtutay that he still has a very positive view of the business, but believes the company isn't worth as much as it has been trading at. "The market can beg to differ," he said. 3:35 p.m.: Twitter has no shortage of co-founders. AP's @liedtkesfc tries to track down the one who wasn't @NYSE for opening Here's his account: While Twitter founders Jack Dorsey, Evan Williams and Biz Stone were in New York celebrating the company's stock debut Thursday, a former partner involved in Twitter's creation was in the midst of a home improvement project on the other side of the country. At least that's how it looked when I swung by the home of Noah Glass, @noah, in San Francisco's Mission District neighborhood. Glass, 43, says he and Dorsey conceived Twitter during a brainstorming session after a night of drinking in San Francisco nearly eight years ago. Dorsey has a different account, maintaining he came up with the idea himself on a San Francisco playground. Tweets and blog posts from 2006 make it clear Glass was deeply involved. He even came up with the service's name, originally shortening it to "twittr." For reasons that aren't entirely clear, Glass was ousted from Twitter before it turned into a cultural phenomenon and didn't even get much company stock, according to a new book about Twitter's history. I was curious to see how Glass was handling this momentous day for Twitter. So I hopped on a train near Twitter's San Francisco headquarters and rode the subway to the next stop. Glass lives with his 7-month-old daughter and the baby's French-speaking mother at the end of a dirt lot in a small home that was set up after a 1906 earthquake destroyed much of the city. These homes are still known as "earthquake shacks." The front gate was open, as was the front door. As I walked up to the threshold, I could hear the pounding of a hammer in the back and a baby blissfully playing in a stroller. The French-accented woman nearby cheerfully greeted me, but when I told her that I was a reporter wondering if Noah wanted to talk to me about Twitter, she informed me that he wasn't interested. She was very nice about it, and we wished me a very nice day. It seemed like a happy home, even if it isn't as grandiose as the mansions that many Twitter employees can now afford to buy. #ForgottenFounder More on the founders: http://bigstory.ap.org/article/flock-feathered-twitters-nest 3:25 p.m.: @Twitter CEO @DickC says growth is just a question of connecting with potential new users Twitter CEO Dick Costolo appeared on CNBC ahead of his company's trading debut at the NYSE to talk about his company and its potential for growth. CNBC's David Faber said that joining Twitter made sense for Faber and a lot of other people early on. But he asked how the company planned to keep growing and attract users outside of its traditional base. Costolo said that it's all about making connections with people and helping them see how Twitter fits into their lives. It's all about, for us, helping people bridge that gap between 'I've heard about Twitter,' to getting exactly where you and so many other people here today are. 3:05 p.m.: AP's @liedtkesfc explores the neighborhood outside @Twitter HQ and sees contrasts. The San Francisco neighborhood outside Twitter's headquarters provides a forlorn contrast to the suddenly rich people working inside the building. These are among the meaner streets in downtown San Francisco, long populated with the destitute who have no place to live and the miscreants who resort to crime to make ends meet. In hopes of cleaning the area up, the city of San Francisco gave Twitter local tax breaks on employee stock options to help persuade the company to move into the neighborhood two years ago. But times are still tough here. Scruffy-looking people gathered against the wall of a post office across the street from Twitter's headquarters. Four of them had just spent the night in a homeless shelter. All of them said that they wished that they owned Twitter stock, yet they maintained that they didn't really envy Twitter employees becoming wealthier as the stock soared Thursday. There was a clump of litter just a few feet away. Amid the empty coffee cups, cigarette butts and empty liquor bottles, there were two scratch-off games for the California lottery that had been discarded because they didn't pay off. #LandofBrokenDreams 2:50 p.m.: In Asia, @Twitter has competition from local companies, reports AP's @YKLeeAP But growth has slowed in South Korea and Japan, a red flag for Twitter as both countries are wealthy and have high rates of mobile device usage - now the predominant way Twitter is accessed. Why are people leaving Twitter or spending less time on it? Too open. Twitter remains blocked from China's vast market but another giant, India, is open to Twitter. It has amassed 27 million users there, according to Semiocast. Yet Twitter acknowledged in IPO filings that low use of smartphones in emerging markets such as India could hamper the ability of advertisers to deliver compelling advertisements and hurt its earnings potential. Youkyung Lee, Seoul, South Korea, @YKLeeAP 2:30 p.m.: @Twitter now among the most valuable media companies, notes AP's @rnakashi Like Twitter, the other large media companies in the country rely to some extent on advertising revenue. As of mid-afternoon, Twitter's value is nearly $33 billion, after including options and restricted stock that'll be available after the IPO. The market value of other media companies: CBS Corp., $34.7 billion; Discovery Communications Inc., $30 billion; Viacom Inc., $38.8 billion; The Walt Disney Co., $120 billion; Time Warner Inc. $60.3 billion.