For those following the smartphone markets, comScore's monthly survey is a strong way to gauge where the heavily contested U.S. market is going. While all surveys are informative, comScore's differs from the traditional market-share surveys from Kantar WorldPanel and Strategy Analytics that focus on sales and shipments during a given time frame, comScore focuses on changes within the subscriber user base by vendor.

Although the two types of surveys may sound similar, they're quite different. Unit sales figures are more volatile as seasonality and a smaller surveyed market can obscure long-term trends. For the entire user base, which includes those new sales and all prior sales still in usage, changes among vendors tend to be slower and more deliberate and serve as the best barometer of the entire market. To further eliminate any signs of seasonality, comScore uses a three-month rolling average in its data.

As for the last comScore survey, the data brings great news for Apple (NASDAQ:AAPL). When it comes to percentage of smartphone subscribers, Apple builds upon its considerable lead in the United States.

Cupertino's growing by poaching
More recently, it seems Apple CEO Tim Cook is obsessed with what he calls Android switchers. The term, which is rather self-explanatory, simply denotes new iPhone users who were previously on Google's Android system through its host of OEM vendors. While Cook has been rather mum on where these vendors are coming from, most industry watchers figure Samsung's (NASDAQOTH:SSNLF) been the victim of this phenomenon as the two compete for high-end subscribers. comScore's data seems to suggest that this is an accurate narrative:

Vendor

July '14

April '15

July '15

Apple

42.4%

43.1%

44.2%

Samsung

28.4%

28.6%

27.3%

LG

6.4%

8.4%

8.7%

Motorola

5.7%

4.9%

4.9%

HTC

4.7%

3.7%

3.5%

Source: comScore.

So as you can see, Apple's increasing its user base. On both a sequential and year-over-year comparison, Apple's winning over more users. Over the past three months, Apple increased its percentage of all U.S. smartphone users (over age 13) 1.1 percentage points, going from 43.1% in April to 44.2% in July's report. On a year-over-year basis Apple picked up 1.8% of the total smartphone market, increasing from 42.4% in that survey.

For Samsung, the past three months haven't been so kind. No vendor lost as much market share over the past three months as Samsung. The company has experienced a 1.3-percentage-point drop over the last reported quarter, going from 28.6% in April to 27.3% in July. Even more interesting is this drop occurred during the timeframe in which Samsung released its high-end Galaxy S6 and Galaxy S6 Edge units, a catalyst that should have stemmed the vendor from defections.

Is the U.S. truly a mature, "upgrade-only" market?
It's important to note that it isn't as if Samsung isn't selling any phones in the U.S.; that's obviously not correct. It's just that the number of phones the company's selling is not enough to offset those being retired and to match user-base increases. And while a popular narrative is the United States has become a mature, upgrade-only market, the number of people with smartphones continues to grow.

According to comScore, 191.4 million people owned smartphones as of its last survey --that's up 10.6% over last year's total of 173 million people. The U.S. does not appear to be quite an upgrade-only market -- at least not yet -- but that's little consolation to Samsung's amid its falling market share.

 

Jamal Carnette owns shares of Apple. The Motley Fool owns and recommends Apple. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.