Abbreviation for Constant Proportion Debt Obligations. They are debt instruments issued by a Special Purpose Vehicle (SPV) which is backed by investment in an index of debt securities, normally credit default swap indices such as iTraxx. They were first launched by ABN-Amro in 2006. They are similar to collateralised debt obligations (CDOs).

See also: http://riskopedia.files.wordpress.com/2007/03/cpdo.pdf, http://www.securitization.net/pdf/DBRS/CDONews8_8Dec06.pdf