Japan's biggest-trading house has had its fill of commodities.

After posting its first annual loss in post-World War II history amid the collapse in commodity prices, Mitsubishi Corp. is shifting away from raw materials to make sure it never happens again. That process is going to take at least three years, according to Chief Financial Officer Kazuyuki Masu.

"We can't post a second net loss," Masu said in an interview in Tokyo. "We are balancing our portfolio so that if the prices of resources fall again, we won't be seeing red. To put it simply, we aren't going to boost our current balance of resources assets" over the next three years.