NYSE holds "successful" dry run for Twitter IPO The New York Stock Exchange says its test run of Twitter's initial public offering on Saturday was a success, as the exchange takes pains to avoid the technical problems that marred Facebook's debut. While the NYSE frequently does testing on the weekend, this was the first time the exchange conducted a mock IPO. Early Saturday, traders from member firms gathered with NYSE staff to run simulated buy and sell orders, test the flow of those orders and open the stock. "This morning's systems test was successful, and we're grateful to all the firms that chose to participate," NYSE spokeswoman Marissa Arnold said in a statement. We are being very methodical in our planning for Twitter's IPO, and are working together with the industry to ensure a world class experience for Twitter, retail investors and all market participants. Twitter will be the biggest technology IPO since Facebook went public in May 2012. The Securities and Exchange Commission later fined Nasdaq $10 million, the largest sum ever levied against an exchange. Twitter, which is expected to go public sometime before Thanksgiving, has chosen to list on the New York Stock Exchange. It plans to sell 70 million shares between $17 and $20 each for a possible take of $1.6 billion. Shares will trade under the ticker "TWTR." This year has been a hot one for IPOs as sharp gains in the stock market have boosted demand for initial public offerings. Over 150 companies have gone public in the U.S. this year, up more than 50 percent from the same period in 2012, according to recent data from IPO tracking firm Renaissance Capital.