By late morning, shares had gained 11.2% to $8.26.
The mobile carrier, the third-largest in the U.S., reported a net loss of 4 cents a share over the three months to March. Analysts surveyed by Thomson Reuters had forecast a loss of 9 cents a share. In the year-ago quarter, Sprint lost 21 cents a share.
Revenue of $8.88 billion exceeded expectations of $8.79 billion.