![iphone 6](https://static-ssl.businessinsider.com/image/54821da1ecad0494608b4567-532-399/iphone-6-120.jpg?maxX=480)
Maxim Shemetov/Reuters
A customer holds the newly released iPhone 6 at a mobile phone shop in Moscow, September 26, 2014.
The iPhone 6 could be harder to find next year as Apple shifts its production ratio toward the 6 Plus, according to UBS analyst Steven Milunovich.
"Given the ramp in [December] we do expect a sequential decline of 40% or so in March, mostly in the smaller iPhone 6," he said. "We think interest in the larger 6 Plus may be greater than Apple expected, necessitating a mix shift."
Asia, particularly China, is driving demand for the 6 Plus.
Barclays recently predicted a strong demand for the 6 Plus this spring, coinciding with the gift-giving during Chinese New Year.
Apple initially underestimated demand for the 6 Plus, resulting in supply shortages.
UBS pointed not only to demand in China, but in the States as well.
"Sales in the US have been 3-to-1 in favor of the smaller iPhone 6, but that may be underestimating true 6 Plus demand given tight supply," said Milunovich.
We'll have to wait until next year to see if Apple can ramp up 6 Plus production without sacrificing iPhone 6 sales.