Around 2005, as the CDO market continued to grow, subprime mortgages began to replace the diversified consumer loans as collateral. By 2004, mortgage-backed securities accounted for more than half of the collateral in CDOs. According to the Financial Crisis Inquiry Report, "the CDO became the engine that powered the mortgage supply chain",[7] promoting an increase in demand for mortgage-backed securities without which lenders would have "had less reason to push so hard to make" non-prime loans.[8] CDOs not only bought crucial tranches of subprime mortgage-backed securities, they provided cash for the initial funding of the securities.[7] Between 2003 and 2007, Wall Street issued almost $700 billion in CDOs that included mortgage-backed securities as collateral.[7] Despite this loss of diversification, CDO tranches were given the same proportion of high ratings by rating agencies[30] on the grounds that mortgages were diversified by region and so "uncorrelated"[31]—though those ratings were lowered after mortgage holders began to default.