A new report by research firm Kantar Worldpanel is noting that Apple’s iOS platform has bumped its market share up 3.5% in the latest three-month period ending in May 2013. All totaled, that’s not really shocking news, but for fans of T-Mobile what they are attributing this rise in market share to might be. So what are they attributing this rise in market-share to? Why the release of the iPhone 5 on T-Mobile of course.

Despite its mid-April release, Kantar says the iPhone 5 was the best-selling smartphone at T-Mobile for the three-month period ending in May. According to their research, the iPhone 5 accounted for 31% of T-Mobile’s total smartphone sales which helped give iOS a bump in market share overall.

Kantar Worldpanel insight director Dominic Sunnebo said:

iOS’ strength on T-Mobile appears to be the ability to attract first time smartphone buyers, upgrading from a featurephone. Of T-Mobile consumers who bought an iOS device since it launched on the carrier, 53% had previously owned a featurephone, well above the market average of 45% of iOS owners who previously owned a featurephone.

Kantar’s research also discovered that 28% of T-Mobile customers planning to change their mobile devices within the coming year are planning to switch to an iPhone.

Even with T-Mobile’s aid in bumping up total iOS market share, Android still maintains a clear lead in the US according to Kantar with 52% of the total market. Apple’s iOS platform follows in second at 41.9%, followed by Windows Phone at 4.6%. Poor BlackBerry, they weren’t even mentioned.

Depending on which research firm data you listen to today, Android and iOS have a duopoly that is responsible for either 91.2% based on comScore data or 93.9% based on Kantar’s data. The bottom line remains that Android and iOS have no close competition in the market and this is very much remains a two-horse race.

TheNextWeb