NEW YORK ( TheStreet) -- IBM ( IBM) beat Wall Street's second-quarter estimate and raised its guidance after market close, despite missing analysts' topline forecast. Excluding the impact of a $1 billion workforce rebalancing charge incurred in the quarter, the tech giant earned $3.91 a share, a year-over-year increase of 8%. IBM, however, brought in revenue of $24.9 billion, down 3% over the same period, or 1% adjusted for currency. Analysts surveyed by Thomson Reuters were looking for earnings of $3.77 a share and sales of $25.37 billion. The company's software revenue rose 4%, or 5% adjusted for currency. Within its software business, key branded middleware revenue grew 9%, or 10% adjusting for currency. IBM's services revenue dipped 4%, or 1% adjusted for currency, but its services backlog was up 3% to $141 billion, or 7% adjusted for the effects of currency. The Armonk, N.Y.-based firm saw revenue from its Systems and Technology business fall 12%, or 11% adjusted for currency, although sales of its System z mainframe climbed 10%, or 11% adjusting for the impact of currency. "In the second quarter, we delivered strong performance in our higher-value software and mainframe businesses and again significantly increased our services backlog on growth in new business," said IBM CEO Ginni Rometty, in a statement released after market close. Rometty added that IBM is confident of achieving its increased 2013 operating EPS expectation of at least $16.90, excluding the $1 billion workforce rebalancing charge. Previously, IBM had forecast operating EPS of at least $16.70. IBM shares climbed 2.45% to $199.49 after market close. --Written by James Rogers in New York. Follow @jamesjrogers >To submit a news tip, send an email to: firstname.lastname@example.org.