Three years after International Business Machines Corp. began trying to turn its "Jeopardy"-winning computer into a big business, revenue from Watson is far from the company's ambitious targets.

IBM Chief Executive Virginia "Ginni" Rometty has told executives she hopes Watson will generate $10 billion in annual revenue within 10 years, according to an October 2013 conference-call transcript reviewed by The Wall Street Journal. She set that target after the executive in charge of Watson said its business plan would bring in $1 billion of revenue a year by 2018. That would make Watson the fastest IBM business unit to reach the $1 billion milestone.

But Watson had total revenue of less than $100 million as of late October, according to the transcript. One of its first big projects, with the University of Texas M.D. Anderson Cancer Center, was "in a ditch" in early 2013, said Manoj Saxena, the executive overseeing Watson.

IBM executives still believe Watson could become one of the biggest innovations in the company's 103-year history, alongside the mainframe and personal computer. In a sign of Watson's potential, IBM plans a major announcement about the business Thursday, said a person familiar with the matter.

"Watson has rapidly moved from an industry-first research initiative to a commercial reality" that tackles business and social problems, an IBM spokesman said. "IBM is making excellent progress with clients and with partners in advancing Watson, and we are excited about Watson's future as a cloud service and as technology that will change lives." Watson also helps IBM sell other technology as customers prepare to use the supercomputer.