Samsung shares fell as much as 5.5% in early trade in Seoul to a four-month low of 1,438,000 South Korean won.
JPMorgan said weak demand for Samsung’s flagship phone, the Galaxy S4, from Europe was likely to impact earnings.
It said it now expects S4 shipments this year to be 20 to 30% lower than its previous forecast.
It said the firm was expected to ship 7 to 8 million units per month from July. Last month, Samsung announced that it had sold 10 million S4 units within a month of the phone’s launch.
JPMorgan analysts were quoted as saying by Bloomberg news agency that the S4’s “peak-quarter number seems way below our previous estimates”.
JPMorgan lowered its 2013 earnings forecast for Samsung by 9%.