In the high-yield credit markets, it is time to party like it's 2006. Companies left for dead a year ago are now finding that investors are clamoring for their high-yield debt. Private equity-backed businesses are paying their owners dividends out of new bond issues. In all, companies raised $11.7 billion last week in the high-yield bond market, the biggest in history, according to Thomson Reuters. The previous record: $11.4 billion, set at the apex of the mid-decade credit boom in November 2006.