MetroPCS Communications on Tuesday offered to acquire rival Leap Wireless International for $5.3bn in stock in a deal that would combine two of the fastest growing mobile carriers to create a new national carrier with over 6.2m subscribers.

Both companies offer their customers unlimited calls in exchange for a flat rate service charge paid in advance and together they would rank as the fifth largest mobile carrier behind AT&T, Verizon Wireless, Sprint Nextel and T-Mobile USA.