Image source: Sprint.

Wireless carrier Sprint (S) has quite a turbulent past. There was the disastrous Nextel acquisition, the lost bet on which 4G technology would emerge as the new standard, and a lack of customer growth in recent years. The SoftBank deal definitely helped strengthen the balance sheet, but many troubles remain at Sprint. The company recently appointed a new CEO, Marcelo Claure, replacing Dan Hesse after Hesse failed to execute on a turnaround.

Due to intense competition, Sprint has now slipped to become the fourth largest wireless carrier in the U.S., making it the smallest of the four major carriers. The customer base has been mostly flat over the past couple of years, fluctuating within a fairly tight range.

As of the most recent quarter (ending Sept. 30, 2015), Sprint had 57.9 million total customers.

Sprint customers | Create column charts

Here is a breakdown of Sprint's customer base since 2013.

Quarter

Postpaid

Prepaid

Wholesale

Q1'13

30.3

15.7

7.9

Q2'13

30.4

15.2

7.7

Q3'13

30.1

15.3

7.9

Q4'13

30.1

15.6

8.2

Q1'14

29.9

15.3

8.4

Q2'14

29.7

14.7

8.9

Q3'14

29.5

14.8

9.7

Q4'14

29.5

15.2

10.2

Q1'15

29.7

15.7

10.7

Q2'15

30

15.3

11.5

Q3'15

30.6

15

12.3

Source: SEC filings. Customer figures in millions.

Claure still has his work cut out for him, and one of his top priorities is getting back in the black.