Investor Warren Buffett listens to a question during a news conference in Madrid May 21, 2008. REUTERS/Andrea Comas

BERLIN (Reuters) - The United States is already in a recession and it will be longer as well as deeper than many people expect, U.S. investor Warren Buffett said in an interview published in German magazine Der Spiegel on Saturday.

He said the United States was “already in recession” and added: “Perhaps not in the sense that economists would define it” with two consecutive quarters of negative growth.

“But the people are already feeling the effects,” said Buffett, the world’s richest man. “It will be deeper and last longer than many think.”

But he said that won’t stop him from investing in selected companies and said he remained interested in well-managed German family-owned companies.

“If the world were falling apart I’d still invest in companies,” he said.

Buffett also renewed his criticism of derivatives trading.

“It’s not right that hundreds of thousands of jobs are being eliminated, that entire industrial sectors in the real economy are being wiped out by financial bets even though the sectors are actually in good health.”

Buffett complained about the lack of effective controls.

“That’s the problem,” he said. “You can’t steer it, you can’t regulate it anymore. You can’t get the genie back in the bottle.”