Essays in Corporate Finance

Prior research has been divided regarding how firms respond to bankruptcy risk, largely revolving around two competing forces. On the one hand, asset substitution encourages firms to increase the riskiness of assets to extract value from creditors. On the other, firms want to minimize bankruptcy risk, either by reducing cash flow risk or through increasing the size of the firm. I test these two theories using a natural experiment of chemicals used in production processes being newly identified as carcinogenic to explore how firms may respond to potential negative cash flow resulting from litigation risk. I use plantlevel chemical data to study firm exposure to risk. I examine how responses between firms of differing levels of chemical exposure may vary within the industry, how firm financial distress affects firm response and whether public and private firms respond differently. In general, my research provides support for the asset substitution theory. My first paper studies how investment response varies based on level of carcinogenic exposure. I find that firms with moderate levels of exposure make efforts to mitigate their cash flow risk and reduce their exposure. At the same time, firms with high levels of exposure increase their exposure and riskiness of future cash flows. These findings are consistent with asset substitution theory. My second paper analyzes the interaction of financial distress and risk exposure. I find that firms in a stronger financial position are more likely to limit their exposure by reducing the number of exposed facilities. On the other hand, not only do firms in weaker financial position not decrease their exposure, I find that, in some instances, they increase their exposure to carcinogens. This work again supports the theory of asset substitution. Finally, in my third paper, I explore if public firms respond differently to a potential negative cash flow shock than do private firms. I test whether existing public firms are more likely to attempt to minimize their cash flow risk and thus reduce their carcinogen exposure than are private firms. I do not find evidence that public firms respond differently to this shock than do private firms.

Exploring the Function and Regulation of Arabidopsis EIN2 in Ethylene Signaling

Ethylene is an essential plant hormone involved in nearly all stages of plant growth and development. EIN2 (ETHYLENE INSENSITIVE2) is a master positive regulator in the ethylene signaling pathway, consisting of an N-terminal domain and a C-terminal domain. The EIN2 N-terminal domain localizes to the endoplasmic reticulum (ER) membrane and shows sequence similarity to Nramp metal ion transporters. The cytosolic C-terminal domain is unique to plants and signals downstream. There have been several major gaps in our knowledge of EIN2 function. It was unknown how the ethylene signal gets relayed from the known upstream component CTR1 (CONSTITUTIVE RESPONSE1) a Ser/Thr kinase at the ER, to EIN2. How the ethylene signal was transduced from EIN2 to the next downstream component transcription factor EIN3 (ETHYLENE INSENSITIVE3) in the nucleus was also unknown. The N-terminal domain of EIN2 shows homology to Nramp metal ion transporters and whether EIN2 can also function as a metal transporter has been a question plaguing the ethylene field for almost two decades. Here, EIN2 was found to interact with the CTR1 protein kinase, leading to the discovery that CTR1 phosphorylates the C-terminal domain of EIN2 in Arabidopsis thaliana. Using tags at the termini of EIN2, it was deduced that in the presence of ethylene, the EIN2 C-terminal domain is cleaved and translocates into the nucleus, where it could somehow activate downstream ethylene responses. The EIN2 C-terminal domain interacts with nuclear proteins, RTE3 and EER5, which are components of the TREX-2 mRNA export complex, although the role of these interactions remains unclear. The EIN2 N-terminal domain was found to be capable of divalent metal transport when expressed in E. coli and S. cerevisiae leading to the hypothesis that metal transport plays a role in ethylene signaling. This hypothesis was tested using a novel missense allele, ein2 G36E, substituting a highly conserved residue that is required for metal transport in Nramp proteins. This G36E substitution did not disrupt metal ion transport of EIN2, but the ethylene insensitive phenotype of this mutant indicates that the EIN2 N-terminal domain is important for positively regulating the C-terminal domain. The defect of the ein2 G36E mutant does not prevent proper expression or subcellular localization, but might affect protein modifications. The ein2 G36E allele is partially dominant, mostly likely displaying haploinsufficiency. Overexpression of the EIN2 N-terminal domain in the ein2 G36E mutant did not rescue ethylene insensitivity, suggesting the N-terminal domain functions in cis to regulate the C-terminal domain. These findings advance our knowledge of EIN2, which is critical to understanding ethylene signaling.