The market’s anticipation of big sales of new iPhones drove Apple shares higher this year, but now one Wall Street firm says the smartphone maker’s stock has risen too far.

Deutsche Bank reiterated its hold rating for Apple shares, saying Wall Street’s consensus estimate for future iPhone sales are too high.

“We remain wary that investor expectations for the iPhone 8/X cycle are more optimistic than realistic,” analyst Sherri Scribner wrote in a note to clients Wednesday entitled “Expectations are pricing in more than Apple can chew.”

“Given the substantial additional upside needed to drive further share gains from here, and our view that FY-19 estimates need to come down to realistically reflect a year after a strong cycle, we see modest downside risk to shares near-term,” she added.

Apple shares fell 0.7 percent in early trading Thursday after the report.

The shares have lost about $50 billion in market value so far this month, falling 6 percent. Despite recent weakness, Apple is still one of the market’s best-performing large-cap stocks, rallying 33 percent this year through Wednesday versus the S&P 500’s 12 percent gain.

The analyst reaffirmed her $140 price target for Apple shares, which is 9 percent higher than Wednesday’s closing price.

Scribner said investors are expecting fiscal 2018 to be a repeat of the big iPhone 6 upgrade cycle in fiscal 2015, when the company generated sales $31 billion above expectations.

“To beat expectations by a similar magnitude ($30B) this cycle would require that AAPL ship 45M more iPhone units in FY-18 than current expectations, or nearly 290M iPhones in total. We view this as highly unlikely,” she wrote.

She is more pessimistic for the following year and predicts Apple’s fiscal 2019 sales will drop.

“We believe it is more likely that unit forecasts decline, similar to the iPhone 6s cycle, and Street estimates for FY-19 need to come down to reflect a more realistic down year following the iPhone 8/X cycle,” the analyst wrote.

Apple did not immediately respond to a request for comment.