T-Mobile US Inc. said Friday that Sprint saw total wireless net additions of 538,000 in the March quarter, or 502,000 postpaid net additions. Despite postpaid phone losses of 348,000 for Sprint, it saw 850,000 net data-device additions. Postpaid churn increased by 5 basis points on a year-over-year basis, to 1.86%. T-Mobile and Sprint completed their merger on April 1 and T-Mobile said in a filing that the standalone Sprint results were calculated using Sprint’s pre-merger reporting policies. “[T]he customer results presented here will end up being materially lower once T-Mobile reporting policies are applied and Sprint Prepaid brands are divested,” the company said in its filing. T-Mobile expects to release standalone financial and operational results for Sprint in May “once the pre-merger Sprint standalone fiscal year-end audit is complete.” T-Mobile shares are off 1.7% in premarket trading Friday. They’ve increased 11% over the past three months as the S&P 500 has declined 13%.Market Pulse Stories are Rapid-fire, short news bursts on stocks and markets as they move. Visit MarketWatch.com for more information on this news.