Samsung's flagship model, the Galaxy S7 Edge was in fifth place with around 25 million units shipped.

The U.S. technology giant shipped around 60 million iPhone 6s units in 2016, IHS Markit data showed, but the company declined to provide the exact figure. The iPhone 7 was the second most-shipped smartphone model with just over 50 million units, while the iPhone 7 Plus was next with just over 25 million.

year-and-half old iPhone 6s was the best-selling smartphone globally last year, beating newer rivals such as Galaxy S7 models, according to new research.

"Apple again has demonstrated that its new iPhones integrate enough innovations and new features to drive sales and remain successful in the market. The company is also capable of selling older devices for an extended period of time. For instance, the year-old iPhone 6s and 6s Plus were both among the most-shipped models in 2016," IHS said in a press release.

The iPhone 6s was released in the fourth quarter of 2015.

Meanwhile, Samsung's S7 and S7 Edge were unveiled in February 2016. They ranked ninth and fifth respectively, but IHS Markit noted that combined shipments of both devices in 2016 was 10 million higher than the predecessor S6 and S6 Edge over the same period. The S7 models got a boost after Samsung recalled the Note 7 when devices began catching fire. This meant that Samsung was one flagship device down, pushing fans of the brand to buy the S7.

But Samsung claimed five spots out of the top 10 most-shipped smartphones in 2016, thanks to its mid-tier devices in the J series which are aimed at emerging markets.

"The company has seen shipment unit gains in the mid to low-tier segment, relative to 2015, due to growth in emerging markets," IHS Markit noted. Samsung is still the biggest smartphone maker in the world by overall shipments.

Samsung is gearing up to release its next flagship – the Galaxy S8 – next week which it hopes will boost its smartphone business.

Huawei which has been growing rapidly and is now the third biggest smartphone player, had no phones in the top 10 most-shipped.