Mitt Romney is defending his decision not to release more than two years of tax information, saying he's "not a business."

Romney's defense comes in an interview with Bloomberg Businessweek. The Republican candidate, who likes to approach issues like the company CEO he used to be, was asked why voters shouldn't see more of his financial information as an investor would want to see before putting money into a company.

"I'm not a business," Romney said. "We have a process in this country, which was established by law, which provides for the transparency which candidates are required to meet. I have met with that requirement with full financial disclosure of all my investments."

President Obama has criticized Romney for not releasing more tax information, and challenged him to be an "open book" like his father. When George Romney ran for president in 1968, he released 12 years of tax returns.

Mitt Romney has released his return for 2010 and an estimate of what he's paid for 2011. He has said he is following the lead of Sen. John McCain, who released two years of tax information when he was the 2008 GOP presidential nominee.

Romney's "I'm not a business" comment brings to mind his exchange with a heckler at the Iowa State Fair last summer. The Iowan had suggested taxes should be raised on corporations to balance the budget and Romney responded: "Corporations are people, my friend."

Romney was roundly mocked by Democrats for his comment last summer. Today, the Democratic National Committee circulated news coverage of his Bloomberg Businessweek comments.