Sen. Elizabeth Warren, D-Mass., laughed off criticism from billionaire businessman Howard Schultz on her new plan to break up big tech.

The 2020 presidential candidate on Friday called for the federal government to break up Facebook, Google and Amazon, offering up a proposal that would recategorize the companies as "platform utilities" and reverse some major tech acquisitions.

Under the plan, companies with more than $25 billion in global revenue that also act as "an online marketplace, an exchange, or a platform for connecting third parties" would be classified as "platform utilities" that would no longer be able to own a platform and its participants.

Schultz, a former Starbucks CEO who has said he might run for president in 2020 as an independent candidate, called the proposal "inconsistent with our free-enterprise system" and "emblematic of Democrats proposing ... fantasy ideas that will never be implemented."

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"A billionaire, right?" Warren said with a laugh, referring to Schultz, when asked in an interview for CBS News' "Face the Nation" about his criticism.

"You mean we could ask these multibillion-dollar companies nicely if they would not eat up the competition and just behave better in the marketplace," Warren said, speaking with CBS at the South by Southwest conference in Austin, Texas. "Really? We've had laws around against antitrust activity and predatory pricing for over a hundred years because we understand that the way markets work are when there's real competition in that market."

Earlier in the interview, Warren said her plan was a necessary solution for tech giants who are right now "eating up little, tiny businesses, startups — and competing unfairly."

"So what I'm saying is, we've got to break these guys apart," she added. "You want to run a platform? That's fine. You don't get to run a whole bunch of the businesses as well. You want to run a business? That's fine. You don't get to run the platform."

Warren used a baseball analogy to compare the current state of play in big tech.

"Think of it this way, it's like in baseball," she said. "You can be the umpire or you can own one of the teams, but you don't get to be the umpire and own the teams."

Warren said century-old antitrust law provides the government with the ability to break up the big tech companies, reversing deals like Amazon's purchase of Whole Foods or Facebook's acquisition of Instagram.

"You know, I think of it this way: I like markets. I think markets produce a lot of good," Warren said. "But markets have to have rules, and so when everybody starts out, think of it like a plowed field. You know, everybody starts out, they plant their seeds, they make it go. That's great as long as everybody's competing. But when one gets so big that it means nobody else gets a chance to compete — including no consumer gets any more choice — then we got a problem. And that's what antitrust laws are for."