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FORTUNE — Given the magnitude of recent telecom deals — Microsoft MSFT offering $7.2 billion for Nokia’s NOK handset business, Google GOOG shelling out $12.5 billion for Motorola Mobility, Verizon VZ paying an astonishing $130 billion to buy out Vodafone’s VOD 45% stake  — Consumer Intelligence Research Partners asks an interesting question:

What matters most to smartphone customers, the carrier, the operating system or the brand?

The answer, based on a survey of 2,000 U.S. customers conducted between July 2012 and June 2013:

  • 85% stick with their carriers (Verizon, AT&T, etc.)
  • 63% stick with their operating system (iOS, Android, etc.)
  • 41% stick with the brand (Samsung, Apple, etc.)

The exception is Apple AAPL , which dominates in terms of both brand and OS loyalty. In fact, iPhone owners are nearly as loyal to iOS (81%) and the Apple brand (82%) as most customers are to their carriers (85%). Only Android (68%) comes close.

According to a report issued Thursday to CIRP clients — and obtained by Fortune — this

… puts into perspective the attractive prices that the operating system makers paid for the smartphone brands, and the high valuation attached to mobile carrier deals, including the recent one for Verizon Wireless.

Of course, a smartphone manufacturer needs to connect to the right operating system. Unfortunately for Nokia, the Microsoft Windows Mobile operating system has a much lower customer retention rate than Apple iOS and Google Android.