Investing.com -- International Business Machines (NYSE: IBM) shares jumped 7.7% in after-hours trading Wednesday after the technology giant reported fourth-quarter results that exceeded analyst expectations, driven by strong software performance and robust mainframe adoption.

IBM posted adjusted earnings per share of $4.52, beating the analyst estimate of $4.29 by $0.23. Revenue climbed 12% YoY (9% at constant currency) to $19.7 billion, surpassing the consensus estimate of $19.22 billion. The company's generative AI book of business has now reached more than $12.5 billion.

"In the fourth quarter, we delivered strong revenue growth, with double-digit Software performance. Additionally, Infrastructure continued its double-digit revenue growth with the robust adoption of the next generation of our mainframe platform," said Arvind Krishna, IBM chairman, president and chief executive officer.

Software revenue increased 14% (11% at constant currency), while Infrastructure revenue surged 21% (17% at constant currency), highlighted by a 67% jump in IBM Z mainframe revenue. Consulting revenue grew more modestly at 3% (1% at constant currency).

For the full year 2025, IBM reported revenue of $67.5 billion, up 8% YoY (6% at constant currency). The company generated $14.7 billion in free cash flow, up $2.0 billion from the previous year.

Looking ahead to 2026, IBM expects constant currency revenue growth of more than 5% and an increase of about $1 billion in year-over-year free cash flow. Currency is expected to provide approximately a half-point tailwind to growth for the year.

"We enter 2026 with momentum and in a position of strength, giving us confidence in our full-year expectations," Krishna added.

The company declared a quarterly cash dividend of $1.68 per common share, payable on March 10, 2026, to stockholders of record on February 10, 2026.