In thinking about how to regulate shadow banking, we must be mindful that it is not really a single system. It is immeasurably more complicated than the bank deposit system of either the 1930s or today. Even with the reduction in activity following the crisis, the scale of shadow banking activity remains very large.
Banks and broker-dealers currently borrow about $ trillion, much of this from money market funds and securities lenders, through triparty repos, leaving aside additional funds sourced from asset managers and other investors through other channels.2 The banks and broker dealers, in turn, use reverse repo to provide  2  Federal Reserve Bank of New York, “Tri-Party Repo Statistics as of 10/09/2013 (PDF),” Tri-Party Statistical Data file.