목차
Title page 1
Contents 1
Abstract 2
1. Introduction 3
2. Data and Measurement 10
2.1. Data Construction and Key Measurement Methods 10
2.2. Validation of Measurement 12
3. Contribution of Mega Firms to Novel Innovation 15
3.1. Aggregate Trend 15
3.2. Firm-level Evidence 21
3.3. Trends in Mega Firms' Share of Novel and Impactful Innovation: An Alternative Measure 23
4. Technological Impact and Knowledge Diffusion 25
4.1. Follow-on Patents 25
4.2. Self-follow-on Patents 27
5. Potential Driving Factors 28
5.1. Cash Holdings by Mega Firms 29
5.2. Size versus Technological Scope of Inventor Teams 32
5.3. Discussion 36
6. Conclusion 38
References 39
A. Appendix 44
Tables 13
Table 1. Novel Patents and Other Measures of Novelty and Creative Destruction 13
Table 2. Impact of Novel Patents 15
Table 3. Firm-level Regressions of Novel Patents by Mega Firms in 1980-2016 22
Table 4. Follow-on Patents on Novel Patents by Mega Firms 26
Table 5. Self-follow-on Rates of Novel Patents over the First Five Years 28
Figures 16
Figure 1. Share of Novel Patent Applications By Mega Firms 16
Figure 2. The Number of Novel Patents by Mega vs. Nonmega Firms 18
Figure 3. The Number of Novel Patents and Their Share in Total Patent Applications 20
Figure 4. Share of Patents Filed by Mega Firms Across Novelty and Impact Groups 24
Figure 5. Percent Change in Patent Applications Following An Increase In Cash Holdings 31
Figure 6. Log Difference in Cash Holdings Between Mega Firms and Non-mega Firms 32
Figure 7. Log Difference in Inventor Team Size Between Mega Firms and Non-mega Firms 34
Figure 8. Log Difference in Technology Scope Between Mega Firms and Non-mega Firms 35
Appendix Tables 46
Table A1. Novel Patents & Number of New Bigrams 46
Table A2. Novel Patents and Patent Creativity 46
Table A3. Novel Patents and Backward Self-citation Ratio 47
Table A4. Novel Patents and Market Valuation 47
Table A5. Novel Patents and 5-year Forward Citations 49
Table A6. Novel Patents and Breakthrough Patents 49
Table A7. Forward Citations on Novel Patents by Mega Firms 54
Table A8. Self-forward-citation Rates of Novel Patents by Mega Firms 55
Appendix Figures 44
Figure A1. Visual image of the novel patent example in the Introduction 44
Figure A2. Trend in the Average Stock Market Valuations and Share of Novel Patents 48
Figure A3. Decomposition of Mega Firms' Share in Novel Patents 50
Figure A4. Trends in Mega Firms' Share in Novel Patents Under Alternative Definitions of Mega Firms 51
Figure A5. Percent Change in Novel Patent Applications by Mega Firms: Contribution by Continuers vs. Change in Composition 53
