Sprint Nextel stock tumbled as the company came out with its quarterly earnings report Thursday, in which it highlighted improved customer service but also announced a higher-than-expected net loss of $847 million as well as a loss of 101,000 postpaid subscribers. Wall Street analysts weren't surprised to see the company, facing stiff competition in the crowded mobile marketplace, announce a net loss, but some were expecting to see a dip closer to $500 million. Wireless contract subscriber losses were higher than expected as well, as 101,000 customers left.