Over the past 10 iPhone announcements — going back to Steve Jobs' introduction of the first iPhone on Jan. 9, 2007 — on the day of the big reveal, Apple ends the day negative 80 percent of the time, new data from Kensho's Bhavesh Dayalji and CNBC's quantitative analysis team show.
But the day after the iPhone announcement, Apple is positive 70 percent of the time by an average of almost 1 percent, according to the Kensho study. This graphic shows how the stock has moved historically on and after Apple announcement days.
In a separate study on Tuesday, UBS said Apple share prices will likely rally after Wednesday's expected announcement and then fade after the launch.
The iPhone 5 announcement was the first major announcement after Tim Cook took over as CEO. The iPhone 6 and 6 Plus announcement was packaged together with the introduction of Apple Watch and Apple Pay, helping to deliver a 3.07 percent next day bump to the stock.
This year, expectations for the new iPhone are somewhat muted, so the introduction of even a modest upgrade — like better iPhone battery life — could drive the stock higher, said Piper Jaffray analyst Gene Munster.
Here is what analysts and Apple watchers are expecting Apple's new iPhone to look like: an updated design — with the biggest change likely to be the removal of the headphone jack — a new black color, tweaked antenna lines, new cameras including a dual lens camera for the iPhone 7 Plus, a doubling in storage capacity of the entry level device to 32G, and an increase in storage capacity to 256G for the most expensive device.
"We're not saying iPhone 7 is a game changer, we are saying it's going to be a solid upgrade, high quality product that will return the iPhone and Apple to growth in 2017," said Drexel Hamilton analyst Brian White. "I think you are still in this gloom-and-doom cycle, but off the bottom."
Apple's stock, profits and sales likely bottomed in the second quarter of fiscal year 2016 and Wednesday's event could mark a turning point, he said. Though people have continued to doubt Apple's ability to innovate, they will find that the company is simply suffering because the iPhone 6's success has been impossible to match.
"A healthy upgrade — that's really all we need," said White.
If you are wondering which stocks could also benefit from a next day Apple bump, these have been the top performing suppliers after an Apple iPhone announcement, posting the following gains on average: Micron (2.08 percent), Corning (1.95 percent), Intersil (1.30 percent) and Qualcomm (0.83 percent), a Kensho study found.
The iPhone 7 is likely to go on sale on Sept. 16, a week earlier than the new iPhone was made available last year, which should help Apple's September quarter sales.
It all adds up to a return to growth for Apple's iPhone starting in the second quarter of fiscal year 2017, said White. In general, analysts expect Apple to return to growth some time in fiscal year 2017, powered perhaps a new 10th anniversary iPhone 8 model with a slew of upgrades.
Disclosure: NBCUniversal, parent of CNBC, is a minority investor in Kensho.