Apple's impressive App Store growth continues to be overlooked by Wall Street, Macquarie says

Analyst Ben Schachter on Friday issued a note to investors, a copy of which was provided to AppleInsider, in which he noted that the App Store is the fastest growing operating profit driver for Apple. For the full calendar year 2015, Apple is on pace to generate more than $5 billion in operating profit, accounting for 45 percent of expected operating profit growth.

Schachter expects that by fiscal year 2017, Apple's services business will grow to about 10 percent of the company's sales and nearly a quarter of its earnings before interest and tax.

"Our focus remains on app sales," he wrote. "Given the massive coverage of AAPL's hardware supply chain, we continue to differentiate by focusing on software and services, and in particular, on apps."

To Schachter, if iPhone sales flatten or begin to decline, the iOS App Store will be a key drive of gross and operating profit growth. In his view, Apple's App Store business is "underappreciated" by investors.

Apple announced earlier this week that it has paid about $8 billion to developers thus far in 2015. That implies more than $11 billion in gross billings and $3.4 billion in net revenues, based on the company's 30 percent cut of all sales.

Since the App Store launched in 2008, Apple has paid $33 billion to developers.