Sprint has just revealed its Q4 2013 earnings, and despite increasing its postpaid subscriber base to a record 53.9 million, it still managed a net loss of $1 billion -- nearly four times worse than last quarter. That continues the US carrier's recent losing streak, and is especially notable during a holiday period when AT&T, Verizon and T-Mobile all had gangbuster quarters. On the plus side, it managed to hit its LTE coverage goal of 200 million people, but that figure is still the lowest of all the major carriers. It also sold 5.6 million smartphones compared to 5 million last quarter, with 20.5 million sold for the year. That accounts for 95 percent of postpaid subscriber sales, which tops its main competitors. With few other financial bright spots, though, new owner Softbank might be wondering what it got itself into.