The results were even worse than the bank initially expected due to slower upgrade demand in developed countries, UBS analyst Steven Milunovich said Wednesday.
"We're finding that there is a bit of a shift toward older phones. Perhaps the fact that the features of the 6S aren't encouraging enough, people are taking the $100 off and buying more of the 6," he told CNBC's "Squawk Alley."
The survey found that search traffic for the iPhone declined about 20 percent in the United States, according to Milunovich in his research note. It also showed that 67 percent of December U.S. iPhone sales were the newest 6S and 6S Plus models, down from the 75 percent new model mix last year.
A number of Apple suppliers have recently warned that their quarterly results would likely be below estimates, adding to ongoing concerns about the prospects for the tech giant's stock, which was below $95 a share midday Wednesday.
Still, Milunovich maintained his "buy" rating with a price target of $130 for Apple. Though this quarter will most likely not help the stock, the primary issue affecting the company is more about the demand for upgrades rather than market share loss or substantial margin pressure, he said.
"There also seems to be little investor faith in current or potential new products, which we think might prove too bearish. Consequently, we are inclined to take our short-term lumps and maintain the buy rating given a solid franchise," Milunovich wrote in his research note.
While Apple is not seeing the upgrade demand in developed countries, the search volumes overseas for new Apple products are "fairly good," according to Milunovich.
"Over the next couple of years, we do think that Apple is going to begin to gain share," said Milunovich. "A lot of what we are talking about is the timing of upgrades, but the Apple ecosystem appears to be as strong as ever."
Disclosure: UBS and/or its affiliates have received compensation from Apple in the last 12 months. A U.S .-based equity strategist, a member of his team, or one of their household members has a long common stock position in Apple.