Here is a great article from the Federal Reserve Bank of San Francisco research department on a study of bank lending and how the expansion in credit over the last 50 years or so had caused the ratio to GDP to have quadrupled in advanced economies.
A dramatic growth caused mainly in mortgage loans backed by real estate.
They are calling this the “Great Mortgaging” which has had a profound influence on the dynamics of business cycles.
Here is what the Federal Reserve had concluded from the study:
“The vast expansion of bank lending after World War II is one of the most extraordinary developments in the history of modern finance and macroeconomics. Our research suggests that the explosion of credit has played a more important role in shaping the business cycle than has been appreciated up to now.
A growing consensus along these lines has renewed interest in revisiting the assumptions about cyclical macroprudential policy (for example, Aikman, Haldane, and Nelson 2014). Much of the recent expansion in bank lending took place through real estate lending, and this particular component of the credit mix appears to have the most relevant macroeconomic effects. A natural inference is that economic policy needs to adapt to this new reality.”