The market's anticipation of big sales from Apple's new iPhones drove its shares higher this year, but now one Wall Street firm says demand for its smartphones will be slightly worse than expected.

UBS said its recent survey of consumers pointed to weaker demand for the iPhone, but any financial downside will partly be offset by higher pricing.

Apple shares are down 0.1 percent in Monday's premarket session. "We present results from our semi-annual UBS Evidence Lab Smartphone survey of 6,700 smartphone buyers across five countries. Buying intentions are flattish from a year ago," analyst Steven Milunovich wrote in a note to clients Sunday entitled "UBS Evidence Lab Survey: Supercycle? Not So Much, but Narrative Shifts to Monetizing the Base." "We interpret the results as a signal that Apple has maintained its position around the world but unit growth could be more muted than originally expected. … We think growth will likely slow in the US and Europe given more muted purchase intent."

As a result, Milunovich lowered his 2018 iPhone unit sales growth forecast to 10 percent from 12 percent. He also reduced his Apple fiscal 2018 earnings per share estimate to $11.50 from $11.65.

Apple's "F18 unit growth might not be explosive, but a rising ASP [average selling price] helps," he wrote.

The analyst reaffirmed his buy rating and his $190 price target for Apple shares, representing 9 percent upside to Friday's close.

"If the survey is correct regarding more muted near-term unit growth, the Apple narrative could shift toward monetizing the large iPhone base," he wrote. "As iPhone cyclicality dampens, investor focus will turn to leveraging that base through other products and services. For example, the vast majority of iPhone users don't pay for Apple services — we expect new services to be introduced in coming years."

Apple is one of the market's best-performing large-cap stocks, rallying 51 percent this year through Friday versus the S&P 500's 16 percent gain.

Source: cnbc