(Reuters) - Apple Inc's AAPL.O shares slipped as much as 4 percent after the company said it was struggling to keep up with demand for its large-screen, higher-margin iPhone 7 Plus, potentially reducing sales and profits in the Christmas shopping period.

Apple Chief Executive Tim Cook acknowledged in a post-earnings conference call on Tuesday that strong demand for the phone, which features two cameras, caught the company off-guard.

“The mix that we projected on iPhone 7 Plus is short of what the reality is. So, we are chasing supply there,” Cook said on the call.

The phone has a higher average selling price than the iPhone 7 variant and brings in more money for the company.

Apple forecast profit margins of 38.0-38.5 percent for the current quarter, below the average estimate of 38.8 percent.

Its revenue forecast of $76 billion to $78 billion for the current quarter was slightly higher than the consensus estimate of $75.08 billion.

Some investors, however, had expected a stronger forecast as rival Samsung Electronics Co Ltd 005930.KS struggles to recover from a blow to its reputation after recalling its flagship Galaxy Note 7 phones due to fire hazard.

The Apple Inc. store is seen on the day of the new iPhone 7 smartphone launch in Los Angeles, California, U.S., September 16, 2016. REUTERS/Lucy Nicholson

“Guidance implied iPhone units for December quarter in line with consensus, though expectations had risen into the print given recent Samsung news flow,” Mizuho Securities USA Inc analysts wrote in a note.

Apple shares were down 2.5 percent at $115.30 in afternoon trading, wiping out about $15 billion in market value.

But Wall Street analysts were largely positive. At least six brokerages, including J.P. Morgan and Raymond James, raised their price targets on the stock.

“We take the company’s multiple references to iPhone 7 plus demand likely outstripping supply in (December quarter) as affirmation of the near-term lift to the iPhone business,” Barclays analyst Mark Moskowitz wrote in a note.

Cook said on Tuesday that supply for iPhone 7 will match demand during the quarter, but iPhone 7 Plus may not.

“We believe this means the company could miss 500,000-1 million additional units if iPhone 7 Plus remains constrained through late December,” Piper Jaffray and Co analysts wrote in a client note. The brokerage raised its price target on Apple’s stock to $155 from $151.

Only one brokerage - Stifel - downgraded the stock to “hold” from “buy” and cut its price target to $115 from $130.

The brokerage said the stock could remain within a range of $105-$120 over the next 2-3 quarters until investors were able to get greater insight into potential drivers for the stock.

Of the 48 analysts covering the stock, 40 rate it “buy” or higher, six have a “hold” rating and two “sell” or lower.

The median price target is $131, according to Reuters data.