Howard Marks, the billionaire co-founder and co-chairman of Oaktree Capital Group LLC, says a proposal by Representative Alexandria Ocasio-Cortez to raise tax rates on top earners to as much as 70 percent would be bad for the U.S.

“Americans generally accept the concept of progressive tax rates,” Marks wrote in a memo released Wednesday. “But they must not be punitive and de-motivating.”

Marks took aim at “increasing anti-capitalist sentiment” in his memo.

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Ocasio-Cortez, 29, a first-term congresswoman from the Bronx, New York, floated the idea of raising the top marginal tax rate to 70 percent on incomes above $10 million.

Marks also questioned the efficacy of President Donald Trump’s protectionist policies, arguing tariffs punish consumers by raising the cost of goods while trying to protect jobs.

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