Bloomberg said Tuesday that Arizona would likely be hurt by its new immigration law. It requires authorities to question people about their immigration status if there's reason to suspect they're in the country illegally.
Bloomberg says countries that welcome immigrants prosper.
He says the U.S. has had some "disgraceful" and "stupid periods" in which it tried to close its borders.
Added Bloomberg: "Fortunately, sanity prevailed."
Bloomberg made his remarks during a question-and-answer session after an unrelated technology announcement.