Has the US Finance Industry Become Less Efficient? On the Theory and Measurement of Financial Intermediation

A quantitative investigation of financial intermediation in the United States over the past 130 years yields the following results: (i) the finance industry's share of gross domestic product (GDP) is high in the 1920s, low in the 1960s, and high again after 1980; (ii) most of these variations can be explained by corresponding changes in the quantity of intermediated assets (equity, household and corporate debt, liquidity); (iii) intermediation has constant returns to scale and an annual cost of 1.5-2 percent of intermediated assets; (iv) secular changes in the characteristics of firms and households are quantitatively important.