In the past three years, wholesale connections stemming from mobile virtual network operators (MVNOs) and M2M have climbed by 30 million to hit 70 million across six top carriers.

According to new numbers from GSMA Intelligence, a group including AT&T, T-Mobile, Sprint, US Cellular, Clearwire and Verizon Wireless has seen combined total connection gains of 20 percent over the last two years.

At AT&T, Sprint and T-Mobile, MVNO connections account for more than half of wholesale connections. But the report points out that Sprint’s MVNO connections have declined nearly 12 percent since the second quarter of 2012 due to the carrier working to eliminate inactive MVNO connections.

High-profile Sprint MVNO FreedomPop recently announced hitting 100,000 subscribers and could be poised to build on those numbers as it rolls out free voice and texting plans along with smartphones. AT&T, meanwhile, recently announced plans to acquire prepaid carrier Leap Wireless, a move that will substantially boost AT&T connection numbers.

The report also points out that M2M connections represent nearly 10 percent of all connections for T-Mobile, AT&T and Sprint. Part of those numbers can be attributed to growth in the connected car market. Both AT&T and Sprint have signed deals to provide connectivity for in-car telematics and “infotainment” platforms.