IBM forecast weak earnings for this year after reporting an 8.5 percent fall in fourth-quarter revenue. IBM forecast 2016 adjusted earnings of at least $13.50 per share.

The strong dollar shaved off $7 billion from IBM's 2015 revenue and reduced its profit by $300 million in the fourth quarter, Chief Financial Officer Martin Schroeter said in a conference call with journalists.

"We continue to make significant progress in our transformation to higher value. In 2015, our strategic imperatives of cloud, analytics, mobile, social and security grew 26 percent to $29 billion and now represent 35 percent of our total revenue," said Ginni Rometty, IBM chairman, president and chief executive officer. "We strengthened our existing portfolio while investing aggressively in new opportunities like Watson Health, Watson Internet of Things and hybrid cloud. As we transform to a cognitive solutions and cloud platform company, we are well positioned to continue delivering greater value to our clients and returning capital to our shareholders."

IBM has been shifting away from hardware by selling low-end servers and semiconductors to focus on high-growth areas such as security software and data analytics, besides cloud-based services.

Yet the new businesses have so far failed to make up for revenue lost to divestitures.

IBM's fourth-quarter revenue fell to $22.06 billion in the quarter ended Dec. 31.

Revenue from cloud and mobile computing, data analytics, social and security software, rose about 10 percent in the fourth quarter.

Total revenue adjusted for currency fell 2 percent.

Excluding items, the company earned $4.84 per share.