This paper investigates whether and how individual managers affect corporate behavior and performance. Using a manager-firm matched panel data set, the authors find that manager fixed effects significantly influence a wide range of corporate decisions, including investment, financial, and organizational practices. They identify patterns in managerial decision-making that suggest differences in "style" across managers. Managers with higher performance fixed effects receive higher compensation and are more likely to be found in better-governed firms. The study also links these findings to observable managerial characteristics, finding that older generations of CEOs tend to be more conservative, while MBA-holding managers tend to follow more aggressive strategies. The paper explores why individual managers matter for firm behavior and economic performance, noting that existing research has largely ignored the role of individual managers. It argues that managers may differ in their approach to company growth and financial aggressiveness, with some managers engaging in more external acquisitions and diversification while displaying lower levels of capital expenditures and R&D. The study also finds that managers who are more investment-Q sensitive tend to have lower investment-cash flow sensitivity, suggesting differences in the benchmarks used for investment decisions. The authors use a regression approach to quantify the importance of manager fixed effects for various corporate practices, finding that including these effects increases the adjusted R² of models by more than four percentage points. They also find that manager fixed effects are particularly important for acquisition or diversification decisions, dividend policy, interest coverage, and cost-cutting policy. The study further shows that manager fixed effects are significantly related to performance, with managers who have higher performance fixed effects receiving higher compensation and being more likely to be found in better-governed firms. The paper also examines the relationship between managerial characteristics and corporate decisions, finding that older generations of CEOs are more conservative, while MBA-holding managers tend to follow more aggressive strategies. The study concludes that top executives vary considerably in their management "styles," suggesting a novel approach for corporate finance research. However, it also raises questions about why managers may behave so differently in apparently similar economic environments, and the efficiency implications of these findings. The authors provide some preliminary evidence on these issues, finding that differences in managerial practices are systematically related to differences in performance.This paper investigates whether and how individual managers affect corporate behavior and performance. Using a manager-firm matched panel data set, the authors find that manager fixed effects significantly influence a wide range of corporate decisions, including investment, financial, and organizational practices. They identify patterns in managerial decision-making that suggest differences in "style" across managers. Managers with higher performance fixed effects receive higher compensation and are more likely to be found in better-governed firms. The study also links these findings to observable managerial characteristics, finding that older generations of CEOs tend to be more conservative, while MBA-holding managers tend to follow more aggressive strategies. The paper explores why individual managers matter for firm behavior and economic performance, noting that existing research has largely ignored the role of individual managers. It argues that managers may differ in their approach to company growth and financial aggressiveness, with some managers engaging in more external acquisitions and diversification while displaying lower levels of capital expenditures and R&D. The study also finds that managers who are more investment-Q sensitive tend to have lower investment-cash flow sensitivity, suggesting differences in the benchmarks used for investment decisions. The authors use a regression approach to quantify the importance of manager fixed effects for various corporate practices, finding that including these effects increases the adjusted R² of models by more than four percentage points. They also find that manager fixed effects are particularly important for acquisition or diversification decisions, dividend policy, interest coverage, and cost-cutting policy. The study further shows that manager fixed effects are significantly related to performance, with managers who have higher performance fixed effects receiving higher compensation and being more likely to be found in better-governed firms. The paper also examines the relationship between managerial characteristics and corporate decisions, finding that older generations of CEOs are more conservative, while MBA-holding managers tend to follow more aggressive strategies. The study concludes that top executives vary considerably in their management "styles," suggesting a novel approach for corporate finance research. However, it also raises questions about why managers may behave so differently in apparently similar economic environments, and the efficiency implications of these findings. The authors provide some preliminary evidence on these issues, finding that differences in managerial practices are systematically related to differences in performance.