Consumer Intelligence Research Partners on Monday estimated that Amazon (NASDAQ: AMZN) ended 2015 with 54 million U.S. members for its Prime service, up 35 percent from the previous year.
Netflix ended 2015 with 44.7 million U.S. streaming video subscribers.
Amazon itself, however, has not revealed the official figures so far.
The e-commerce giant is due to report fourth-quarter fiscal year 2015 (4QFY15) results on Thursday after the market closes.
