Yeah, it's called due diligence...

The brainless should not be in banking -- Willem Buiter

No, usually it's just too expensive to pull large data sets like that, so you only do it if you know the person who requested it has the capability of making sense of it.  Few do, since it requires a lot of IT as and finance skills and specialized equipment to analyze large financial data sets. The risk is that someone will look at it and come to the wrong conclusions because they don't know what the data mean.  That said, however, the better purveyors of things like mortgage backed securities, such as GMAC,  did provide useful, detailed data for public inspection accessible by website on each security.  It may have made their securities more valuable in the marketplace, but those securities went bust just like everyone else's, so it wasn't lack of underlying data that kept rating agencies in the dark -- they were selling these things as "sub" prime and "alternate" prime securities after all -- completely open about the fact that these things were backed by junk.  The AAA ratings came from the way bond tranches were organized and insured so that even if things went bad, some investors would still get paid before others (and mostly still are) so that their risk was minimal.  More underlying data about the loans could have added nothing to a rating agencies' judgment, since the rating has almost nothing to do with underlying data about individual loans.