Propelled by the recent financial product innovations involving derivatives, securitization and mortgages, commercial banks are becoming more complex, branching out into many “nontraditional” banking operations beyond issuance of loans. This broadening of operational scope in a pursuit of revenue diversification may be beneficial if banks exhibit scope economies. The existing (two-decade-old) empirical evidence lends no support for such product-scope-driven cost economies in banking, but it is greatly outdated and, surprisingly, there has been little (if any) research on this subject despite the drastic transformations that the U.S. banking industry has undergone over the past two decades in the wake of technological advancements and regulatory changes. Commercial banks have significantly shifted towards nontraditional operations, making the portfolio of products offered by present-day banks very different from that two decades ago. In this paper, we provide new and more robust evidence about scope economies in U.S. commercial banking. We improve upon the prior literature not only by analyzing the most recent data and accounting for banks’ nontraditional off-balance sheet operations, but also in multiple methodological ways. To test for scope economies, we estimate a flexible time-varying-coefficient panel-data quantile regression model which accommodates three-way heterogeneity across banks. Our results provide strong evidence in support of significantly positive scope economies across banks of virtually all sizes. Contrary to earlier studies, we find no empirical corroboration for scope diseconomies.

We develop a novel methodology for the proxy variable identification of firm productivity in the presence of productivity-modifying learning and spillovers, which facilitates a unified internally consistent analysis of the spillover effects among firms. Contrary to the popular two-step empirical approach, ours does not postulate contradictory assumptions about firm productivity across the estimation steps. Instead, we explicitly accommodate cross-sectional dependence in productivity induced by spillovers, which facilitates identification of both the productivity and spillover effects simultaneously. We apply our model to study cross-firm spillovers in China's electric machinery manufacturing, with a particular focus on productivity effects of inbound FDI.

Scope economies resulting from the joint offering of loans and savings accounts (as opposed to loans only) are customarily invoked to promote the transformation of credit-only microfinance institutions (MFIs) into integrated loans-and-savings entities. To ensure robust inference, we estimate scope economies for the microfinance industry using a novel approach which, among its other advantages, accommodates inherent heterogeneity across loans-only and loans-and-savings MFIs as well as controls for endogenous self-selection of institutions into the either type. For analysis, we use a large 2004–2014 Mixmarket dataset. Unlike earlier studies, we do not find prevalent scope economies in the microfinance industry. We find that the median degree of scope economies is statistically indistinguishable from zero and that scope economies are significantly positive for less than a half of loans-and-savings MFIs. For a non-trivial 14% of institutions, the empirical evidence suggests the existence of significantly negative diseconomies of scope indicating that the separate production of loans and savings accounts actually has the potential to reduce an MFI’s costs. We also find that the failure to account for endogenous selectivity dramatically overestimates the degree of scope economies resulting in the failure to detect scope diseconomies among MFIs. Thus, our findings call for caution when invoking scope economies as a blanket justification for universal expansion of the scope of financial operations by MFIs. Instead, promoting integrated loans-and-savings MFIs may be justifiable as a means to meeting the needs of the poor rather than as a way for the industry to save costs.