Apple shares briefly surged more than 4 percent Wednesday to their highest levels in about nine months, as the iPhone 7 cycle begins.
The stock ended the day 3.6 percent higher on Wednesday, its best daily performance since July 27.
The stock held between 3.5 percent to about 4 percent higher in afternoon trade after a Bloomberg report that an AT&T executive said iPhone 7 preorders were "up." Earlier in the afternoon, the stock had pared gains to temporarily trade about 3 percent higher amid another Bloomberg report that cited a comment from a Verizon executive that said iPhone preorder volume was within a normal range.
The stock remained the top gainer in the Dow Jones industrial average for a second-straight day, briefly adding about 30 points to the Dow by itself. Shares were pacing for their first three-day win streak with consecutive gains over 2 percent since April 2013.
The four major carriers offer a free upgrade to the iPhone 7 when users trade in certain older phones and stay on their plan for two years.
"We estimate the carriers are losing (about) $300 per iPhone under the trade-in promos," UBS analyst John Hodulik said in a note Wednesday.
RBC Capital analyst Amit Daryanani reiterated his outperform rating on the stock Wednesday. He says several tailwinds position Apple to outperform from current levels, including the potential for Apple to grab market share given Samsung's woes with Galaxy Note 7.
Apple officially introduced the iPhone 7 and updated Apple Watch last week. The company began taking preorders on Friday for both products.
Apple's new iPhone does not have a headphone jack. Phone users may use Bluetooth products or a new Apple AirPod system instead of wire headphones. The phone also has two rear cameras that will allow users to see a live preview with shallow depth of field. Many Wall Street analysts expected those new features to encourage more iPhone users to upgrade.
Apple also rolled out the latest version of the company's iPhone software, iOS 10, on Tuesday. The launch did not go smoothly, forcing some phones into recovery mode, otherwise known as "bricking."
Apple said the problem was quickly resolved and it apologized to affected customers.
Morgan Stanley analyst Katy Huberty reiterated her overweight rating Wednesday for Apple stock, saying it would beat the consensus forecast if just 25 percent of its existing iPhone users were to upgrade their phones.
Apple joined the Dow on March 19, 2015, after closing the prior day at $128.47. It's not exactly been a stellar performer – down 9.7 percent since then, even with Wednesday's gains. Its low as a Dow member occurred on May 12, when it dipped as low as $89.47 intraday.
— CNBC's Gina Francolla, Peter Schacknow and Anita Balakrishnan contributed to this report.