European sovereign nations have issued debt with negative returns, with Austria being the most recent. Some European corporations have gone negative in the market, but the issuer does not benefit from that. And the sovereign nations in question are core members of the European Union who are not apt to be put through the default wringer to the same extent that Greece was. Nonetheless, the advent of negative interest rates in low-risk sovereign nations does suggest that Europe is entering a world where default is almost impossible, one all too familiar to bankruptcy professionals in the United States.
Source: New York Times, 04/03/2015