By Neil Hughes

Published: 07:50 AM EST (04:50 AM PST)

With the iPad crossing the 2 million sales threshold this week, one prominent analyst now believes Apple will sell 6.2 million devices in calendar year 2010, as many of the company's international stores have limited stock.

Gene Munster with Piper Jaffray issued a note to investors Tuesday, in which he upped his 2010 sales estimates from 4.3 million, citing strong early sales. 6.2 million in 2010 would add another 25 cents to his calendar year 2010 GAAP earnings per share estimates.

However, given ongoing low supplies of the iPad, Munster also cautioned investors that sales could be limited by availability. The analyst said he believes initial international sales over the weekend contributed at least another 100,000 units.

"We conducted 25 checks at Apple stores in the U.K., Germany, France, Japan and Australia, and found that supply exists after the first weekend of sales, but availability is very limited," he wrote.

Among the 14 international sales that were contacted on last Friday's launch day, 29 percent had sold out. Following the launch weekend, another 11 stores were contacted, and 36 percent were entirely sold out. Similar checks among U.S. Apple stores on May 21 found that 74 percent of stores were completely sold out.

"In other words, supply at international stores is limited and declining, similar to trends we saw at U.S. Apple stores," Munster wrote.



Apple announced on Monday that it had sold 2 million iPads in less than two months. That means Apple has sold about 34,000 per day on average, though Munster said numbers through April likely skewed lower than after launch due to limited U.S. supply. Apple reached its first million sales of the iPad in just 28 days.