NEW YORK (TheStreet) -- Sprint's (S - Get Report) shares are soaring by 23.92% to $5.71 today as the company reported better than expected first quarter earnings results before the market open, CNBC's Carl Quintanilla reported on "Squawk on the Street" Monday.

The company reported its highest sub growth in postpaid phone net additions for the first quarter in nine years, Quintanilla said.

Sprint's increase in earnings was driven by reverting back to the fundamentals of business, which is to bring a great product at a great price, Sprint CEO Marcelo Claure told CNBC.

"173,000 postpaid phone net ads which matters in this business is the highest in the last nine years so we're happy with the results and progress we're making," he said.

The company reported postpaid phone churns of 1.39%, the best in company history and improved year-over-year for the sixth consecutive quarter.

Capital expenditures was lower than expected and pre-paid phones face more challenges, Quintanilla said citing analysts.

Sprint has stressed its focus on postpaid because that's where the money is, Claure said.

The company beat Verizon is reliability and beat all three top carriers in speed, Claure said citing PC Magazine's rankings.

"So you don't need to spend the crazy money that carriers have been used to spending. We're going to spend $3 billion. That's good enough. We're going to continue to give great service to our customers," he said.

Sprint is one of the few carriers left that offers an unlimited data plan to its customers.

Sprint is focused on turning the company around, building its handset and wireless business, and returning the company to profitability, Claure said.