Siegel, who co-founded the $35 billion hedge fund Two Sigma, admitted this week he is very worried that machines, aka robots, will cost tons of workers their jobs, according to Bloomberg News.

Speaking at the Milken Institute Global Conference, Siegel echoed what industry leaders including Microsoft (MSFT) co-founder Bill Gates, Tesla and SpaceX co-founder Elon Musk, and Cambridge physicist Stephen Hawking have already said: AI is interesting technology that could have some scary side-effects.

“Most people in the bulk of the job market are not involved in super-high-value jobs. They are doing routine work and tasks and it’s precisely these tasks that computers are going to be better at doing,” Siegel said, citing how the combustion engine replaced horses and ATMs replaced bank tellers, according to Bloomberg.

Two Sigma, which uses advanced quantitative techniques to run its business, is no stranger to artificial intelligence, sometimes known as machine learning. Last month it hosted an AI competition: The goal being to build a system that can play air hockey.

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Early last year, Musk, Hawking, Apple (AAPL) co-founder Steve Wozniak and other business and academic leaders signed an open letter urging careful thinking on AI deployments to ensure beneficial results. At around that same time, Gates took up the subject on a Reddit Ask Me Anything forum, saying the near-term threat of AI is very low but that will change over time.

“First the machines will do a lot of jobs for us and not be super intelligent. That should be positive if we manage it well. A few decades after that though the intelligence is strong enough to be a concern. I agree with Elon Musk and some others on this and don’t understand why some people are not concerned.”

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Gates, reiterated those points during an appearance this week on CNBC’s Squawk Box where he appeared with Berkshire Hathaway (BRKA) vice chairman Charlie Munger.

In the near term, people can use a software agent—which Gates called “alter ego software”—that can understand spoken questions, to prioritize their tasks.

“Now we’re all slaves to email, Twitter, texts and we weigh which is important. Software will take that over and point out what’s a priority,” Gates said.

Not everyone agrees with Gates and Siegel that only low-skill, low-pay jobs are at immediate risk from AI. Speakers at an MIT conference last year, for example, said high-skill professionals including commercial airline pilots are next on the robot hit list.

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AI has promise to improve lives but the tradeoff comes in jobs. In theory, if displaced workers can be trained to perform higher value work, then all is good, but let’s face it, if productivity is boosted, fewer people are needed to do the same amount of work.

During the same CNBC interview, Berkshire Hathaway’s Munger was asked what he liked about IBM’s (IBM) Watson technology or AI in general.

His answer: “I like the idea of using artificial intelligence because we’re so short on the real thing.”