Apple will suffer as consumers are increasingly less willing to buy expensive smartphones, according to one Wall Street firm.

Nomura Instinet reaffirmed its neutral rating on Apple shares, predicting the company will report iPhone unit sales below expectations this year.

"Our demand checks suggest little improvement in iPhone demand in 2018. Corresponding supply chain downticks suggest iPhone expectations have yet to bottom," analyst Jeffrey Kvaal wrote in a note to clients Monday. There are "further signs of trouble at the high end of the market. … One factor that is likely suppressing the smartphone market is price. We see several indications the market elasticity is falling."