CNN has an article based on a new study by a professor at Northwestern showing the chokehold of those with elite academic credentials on elite jobs at Wall Street banks, law firms, and management consultancies: "elite professional service employers" rely more on academic pedigree than any other factor. For recruiters, it's prestige that counts, rather than "content" like grades, courses, internships, or other actual performance. That's because if you got into a "super-elite" school -- which essentially means Harvard, Yale, Princeton, Wharton (University of Pennsylvania), and Stanford -- you must be smart. Plus, time spent at those bastions in turn will make you "polished" and attractive to corporate clients. It is, according to Rivera, a largely self-perpetuating hiring process that prizes efficiency: Why spend effort looking for "that one needle in the haystack" at a "safety school" like the University of Michigan or, heavens forfend, Bowling Green, when the run-of-the-mill Yalie's still a prince. Even "second-tier" Ivies like Brown, according to Rivera, are suspect for the top firms.
This conforms with my own experience. Legal academia, at least in the US, is also very focussed on elite credentials. This does not happen as much in the UK probably because there isn't a large enough supply of candidates with elite credentials for jobs in law schools. Anecdotally, many candidates with doctoral degrees from Oxford and Cambridge - which have small cohorts in any case - seem to seek jobs in law firms, international organizations, etc.