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M&As Efficiency Gains: Evidence from Branch-Level Data

Published online by Cambridge University Press:  25 March 2026

Lucas Argentieri Mariani*
Affiliation:
Bocconi University, BAFFI and IGIER
Bernardo Ricca
Affiliation:
Insper bernardoOGR@insper.edu.br
*
lucas.mariani@unibocconi.it (corresponding author)
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Abstract

We examine how banks reallocate employees following mergers and acquisitions (M&As) and the resulting effects on productivity. Using matched employee–branch data combined with branch-level financial information, we show that M&As expand internal labor markets and trigger substantial worker redeployment. Newly consolidated banks reassign high-ability loan officers to acquirer branches, increasing productivity. Target branches also experience productivity improvements, primarily driven by restructuring and cost reductions. These effects are strongest in municipalities where the combined pre-merger internal labor markets of the target and acquirer were larger, highlighting the central role of internal labor markets in generating efficiency gains from consolidation.

Information

Type
Research Article
Creative Commons
Creative Common License - CCCreative Common License - BY
This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0), which permits unrestricted re-use, distribution and reproduction, provided the original article is properly cited.
Copyright
© The Author(s), 2026. Published by Cambridge University Press on behalf of the Michael G. Foster School of Business, University of Washington
Figure 0

TABLE 1M&As Involving Large Private Banks, 2007–2015TABLE 1 Long description.

Figure 1

FIGURE 1Local Private Market Share in 2006Figure 1 shows the geographical presence of the branches that comprise our sample as of December 2006.FIGURE 1 Long description.

Figure 2

TABLE 2Branch-Level Descriptive StatisticsTABLE 2 Long description.

Figure 3

TABLE 3Acquirer, Target, and Control BranchesTABLE 3 Long description.

Figure 4

TABLE 4M&As and Labor ReallocationTABLE 4 Long description.

Figure 5

TABLE 5M&As and Labor AbilityTABLE 5 Long description.

Figure 6

TABLE 6M&As Effects on Branch OutputTABLE 6 Long description.

Figure 7

TABLE 7M&As and Branch ProductivityTABLE 7 Long description.

Figure 8

TABLE 8M&As and Branch ProfitabilityTABLE 8 Long description.

Figure 9

TABLE 9M&As and Branch ClosingsTABLE 9 Long description.

Figure 10

TABLE 10Consolidated Bank M&A Effects at the Municipality LevelTABLE 10 Long description.

Figure 11

TABLE 11Consolidated Bank M&A Effects and the Role of Local Internal Labor Market (ILM)TABLE 11 Long description.

Figure 12

FIGURE 2Employment ReallocationFigure 2 reports the dynamic effects of M&As on labor reallocation, estimating an augmented version of equation (1) that includes leads and lags of the treatment indicator. Reported 99% confidence intervals are based on standard errors clustered at the branch-cohort and bank-time-cohort levels. Dependent variables are inverse hyperbolic sine transformations of the original variables. All regressions include branch-by-cohort fixed effects, municipality-by-year-by-cohort fixed effects, baseline branch characteristics interacted with time-by-cohort fixed effects, and market power controls interacted with the Post M&A indicator. The estimation sample includes branches that remained open throughout the estimation window (3 years before and 6 years after the events).FIGURE 2 Long description.

Figure 13

FIGURE 3M&A Effects on Branch OutputFigure 3 reports the dynamic effects of M&As on branch output, estimating an augmented version of equation (1) that includes leads and lags of the treatment indicator. Reported 99% confidence intervals are based on standard errors clustered at the branch-cohort and bank-time-cohort levels. Dependent variables are inverse hyperbolic sine transformations of the original variables. All regressions include branch-by-cohort fixed effects, municipality-by-year-by-cohort fixed effects, baseline branch characteristics interacted with time-by-cohort fixed effects, and market power controls interacted with the Post M&A indicator. The estimation sample includes branches that remained open throughout the estimation window (3 years before and 6 years after the events).FIGURE 3 Long description.

Figure 14

FIGURE 4ProductivityFigure 4 reports the dynamic effects of M&As on productivity, estimating an augmented version of equation (1) that includes leads and lags of the treatment indicator. Reported 99% confidence intervals are based on standard errors clustered at the branch-cohort and bank-time-cohort levels. Dependent variables are inverse hyperbolic sine transformations of the original variables. All regressions include branch-by-cohort fixed effects, municipality-by-year-by-cohort fixed effects, baseline branch characteristics interacted with time-by-cohort fixed effects, and market power controls interacted with the Post M&A indicator. The estimation sample includes branches that remained open throughout the estimation window (3 years before and 6 years after the events).FIGURE 4 Long description.

Figure 15

FIGURE 5Branch ClosuresFigure 5 reports the dynamic effects of M&As on branch closures, estimating an augmented version of equation (1) that includes leads and lags of the treatment indicator. Reported 99% confidence intervals are based on standard errors clustered at the branch-cohort and bank-time-cohort levels. The dependent variable is a dummy equal to 1 if a branch has closed. All regressions include branch-by-cohort fixed effects, municipality-by-year-by-cohort fixed effects, baseline branch characteristics interacted with time-by-cohort fixed effects, and market power controls interacted with the Post M&A indicator.FIGURE 5 Long description.

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