ITunes Video Rentals a $1 Billion Business by 2015?

How big is Apple’s iTunes video rental business? In a research note today, Gleacher & Co. analyst Brian Marshall hazards a guess: Apple’s serving about 475,000 rentals a day and raking in upward of $60 million per quarter doing it.

Not too shabby for a service launched in January of 2008. And if its growth follows a trend line similar to that of Netflix–which is certainly within the realm of possibility given sales of next-generation Apple TVs and the popularity of iOS devices like the iPhone and iPad–Marshall figures Apple’s iTunes rental operation will be big business by 2015.

“Over the past five years, Netflix’s subscriber base has quintupled while revenue more than tripled,” says Marshall. “If Apple can grow its related business similarly to Netflix’s historical growth profile, it is feasible iTunes’ annual rental revenue could exceed $1 billion by 2015.”

That’s another $300 million per year for Apple’s bottom line, assuming the company keeps about 30 percent of the total.