But advocates for workers rights may be a little less pleased with the billionaire investor after he published an op-ed in The Wall Street Journal Friday, decrying the efforts in many cities across the United States to raise the minimum wage to as much as $15 per hour.

Buffett admitted that the middle class has increasingly hurt by an economy that rewards people with “specialized talents,” but not the vast majority of Americans who hold “more commonplace skills.” However, Buffett argues that trying to solve the problem of stagnant wages for working Americans by raising the minimum wage is misguided. Writes Buffett:

In my mind, the country’s economic policies should have two main objectives. First, we should wish, in our rich society, for every person who is willing to work to receive income that will provide him or her a decent lifestyle. Second, any plan to do that should not distort our market system, the key element required for growth and prosperity.

That second goal crumbles in the face of any plan to sizably increase the minimum wage. I may wish to have all jobs pay at least $15 an hour. But that minimum would almost certainly reduce employment in a major way, crushing many workers possessing only basic skills. Smaller increases, though obviously welcome, will still leave many hardworking Americans mired in poverty.

Instead, Buffett says, we should expand the earned income tax credit, also known as a “negative income tax,” in which the government subsidizes the wages of workers making under a certain amount. “The EITC rewards work and provides an incentive for workers to improve their skills,” Buffett writes. “Equally important, it does not distort market forces, thereby maximizing employment.”