In the heady days of  2004-2007, before  the Great Moderation came to a shuddering halt, it seemed  set in stone that European investment grade CDS traded tighter than their North American counterparts. In May 2007, the Markit iTraxx Europe was trading at 20bps and the Markit CDX.NA.IG was quoted 15bps wider at 35bps. This 15bps basis was fairly typical of a time when the CDS market was dominated by synthetic CDO issuance.