Chairman and CEO Larry Fink told CNBC on Thursday it is not substituting stock-picking computers for humans.

Right now, machines do not outperform human analysts, Fink said.

Against the backdrop of a fiercely competitive trading environment, BlackRock its active management business by cutting jobs, reducing fees and increasing its use of computers to pick stocks.

BlackRock, the world's biggest money manager, has $5.1 trillion in assets under management.

Fink said on "Squawk Box" he was surprised by the media coverage of the reshuffling because it's only a small part of BlackRock's business.

"We are reorienting some of the humans' jobs in terms of doing more data science and data analysis," Fink said. "We'll have the same amount of employees in our equity division a year from now than we do today."

The move to incorporate more computing power into investment decisions is a recognition that there are so many sources of information that need to be analyzed quickly, Fink said.

"Very fast computers [can] analyze blogs, analyze all the feeds of the internet to come up with different nuances, different fields of information," he said. "It requires model analysis and deep-data analysis."

BlackRock is researching ways to use artificial intelligence, Fink said.

Fink said he believes in active management, but he personally invests in index funds because of all of the investment restrictions he is subject to as chief of BlackRock.

BlackRock has also been aggressive in lowering fees, Fink said.

Read more from Fink's interview: