IBM beat analysts' estimates for second-quarter revenue on Wednesday, riding on strong demand for its software and higher AI-linked spending by clients looking to tap the booming technology, sending its shares up 4% in extended trading.

The company has focused on expanding its Watsonx platform that allows users to deploy chatbots or enhance code for AI programs, while also making its Granite family of AI models open-source to help popularize its AI services.

IBM reported revenue of $15.77 billion, compared with analysts' average estimate of $15.62 billion, according to LSEG data.

Big Blue's stock has gained about 12% so far this year, as investors bank on a rally in shares of AI-linked companies.

Software revenue increased about 7% to $6.74 billion. About 75% of the revenue was recurring, CFO James Kavanaugh told Reuters.

The company's AI Book of Business - a combination of bookings and actual sales across various products - grew to $2 billion, of which about $1 billion was added in the second quarter.

"The commercialization of Generative AI is accelerating, positioning diversified enterprise technology companies like IBM to capitalize on the growing demand for AI integration," said Tejas Dessai, a research analyst at Global X.

Consulting made up 75% of the AI book with the rest coming from software, Kavanaugh said.

Still, consulting revenue fell about 1% to $5.18 billion as clients cut back on discretionary spending and short-term consulting projects.

"You're seeing an overall very dynamic macroeconomic environment, and underneath that, clients are choosing technology for competitive advantage. They are spending on GenAI," Kavanaugh said.

"But they are making trade-off decisions and spending reprioritizations, and you see that play out within consulting."

Companies have prioritized spending on longer-term consulting projects centered on their AI businesses - revenue from which is yet to be reflected in IBM's books.

Second-quarter adjusted profit of $2.43 per share beat estimates of $2.20, helped by robust sales in the high-margin software business.

The mainframe business grew 8% in the second quarter, Kavanaugh said.

IBM's mainframes - data servers with high computing power - are being used to process some of the data used by AI applications.

  - Reuters