"The Dynamics of Firm Size Inequality: The Role of Acquisition and Innovation" (job market paper)
Abstract: What do changes in top sales shares signal about changes in firm dynamics? I use an accounting decomposition to identify two sources of top sales share growth: (i) incumbent top firms grow bigger; (ii) new top firms replace old top firms. Over the 1950-2019 period, incumbent top firms contribute about four times as much as new top firms to the growth of sales share accrued to the top 0.01% firms in the US economy. I then build an analytical framework to estimate a firm dynamics process in which firms grow in response to an own innovation shock and shrink at the impact of a creative destruction shock using the empirical decomposition terms of top share growth. I find that own innovation is the major force that drives top sales share growth. The decline in the top sales shares in the 1980s is associated with a higher aggregate productivity growth, while the rise in the top sales shares since the late 1990s implies a slightly lower productivity growth.
"Employment during the COVID-19 Pandemic: Collapse and Early Recovery" (with Tam Mai)
Abstract: We use monthly Current Population Survey data to document employment changes during the COVID-19 pandemic at the occupation, industry, and metropolitan statistical area (MSA) levels. Over March-April 2020, jobs losses are larger for occupations with higher physical proximity or lower work-from-home feasibility, especially for lower-paying occupations. Nonessential industries also see greater declines in employment. Such occupational and industrial susceptibility to COVID-19 contributes to the variation in employment changes across MSAs: Employment shrinks more for MSAs with larger pre-crisis fractions of workers employed in occupations with higher infection risk. Over April-June 2020, occupations and industries that are hit harder recoup more jobs, but the recovery is only partial. Moreover, the gains are concentrated in lower-paying occupations and a few industries. Taken together, these abrupt changes in employment following the COVID-19 outbreak are unprecedented and potentially have longterm implications for occupational inequality and regional disparity.
Abstract: This paper studies how income inequality at the Metropolitan Statistical Area (MSA) level affect mortgage credit allocation along the income distribution of households within MSAs. I find that MSAlevel income inequality has heterogeneous effect on household-level mortgage debt accumulation. Two measures of inequality, the ratio of 95th-to-80th percentile (p95/p80) and the ratio of 80th-to-50th percentile (p80/p50) of household income, exhibit significant impact. With respect to credit approval along the income distribution, high p95/p80 inequality works more in favor of low-income households while high p80/p50 inequality benefits high-income households more.
Work in Progress
"Scientific Breakthroughs, Entrepreneurial Finance and Firm Dynamics"
Abstract: Access to frontier technology is a major driver of modern economic growth. I seek to understand how entrepreneurial finance promotes the diffusion of frontier knowledge developed in the academia by funding startups that make use of new technologies. I then track how such advanced technologies spread into large firms via acquisitions or via the usage of Corporate Venture Capital (CVC). I empirically identify scientific breakthroughs by performing text analyses on academic research papers and patent documents. One such key scientific breakthrough that I have identified is CRISPR-Cas9. The discovery of the revolutionary gene-editing tool CRISPR-Cas9 in 2012 has resulted in the establishment of a growing list of VC- funded startups wielding this unique powerful tool to solve complex problems in healthcare, agriculture and clean energy.
Publications (in Biomedical Science, from previous PhD study)
Shi, A., Liu, O., Koenig, S., Banerjee, R., Chen, C. C. H., Eimer, S., & Grant, B. D. (2012). RAB-10-GTPase–mediated regulation of endosomal phosphatidylinositol-4, 5-bisphosphate. Proceedings of the National Academy of Sciences, 109(35), E2306-E2315.
Sun, L., Liu, O., Desai, J., Karbassi, F., Sylvain, M. A., Shi, A., & Grant, B. D. (2012). CED-10/Rac1 regulates endocytic recycling through the RAB-5 GAP TBC-2. PLoS genetics, 8(7), e1002785.
Liu, O., & Grant, B. D. (2015). Basolateral endocytic recycling requires RAB-10 and AMPH-1 mediated recruitment of RAB-5 GAP TBC-2 to endosomes. PLoS genetics, 11(9), e1005514.
Wang, P., Liu, H., Wang, Y., Liu, O., Zhang, J., Gleason, A., & Grant, B. D. (2016). RAB-10 promotes EHBP-1 bridging of filamentous actin and tubular recycling endosomes. PLoS genetics, 12(6), e1006093.
(In Chinese) Li XT, Yuan YL, Xia YY, Yu BZ, Zhang TJ, Liu O., Lv XZ, Zhan SY. (2009). Genetic polymorphism of glutathione-S-transferase M1 and T1: a systematic review in Chinese population and a pilot study in smear-positive pulmonary tuberculosis cases of Jilin province. Chinese Journal of Epidemiology, 30(5):502-6.