Hojin Jung

Relationship between oil price and exchange rate by FDA and copula

ABSTRACT This article investigates the relationship between daily crude oil prices and exchange rates. Functional data analysis is used to show the clustering pattern of exchange rates and oil prices over the time period through high dimensional visualizations. We select exchange rates for important currencies related to crude oil prices by using the objective Bayesian variable selection method. The selected sample data exhibits non-normal distribution with fat tails and skewness. Under the non-normality of the return series, we use copula functions that do not require to assume the bivariate normality to consider marginal distribution. In particular, our study applies the popular and powerful statistical methods such as Gaussian copula partial correlations and Gaussian copula marginal regression. We find evidence of significant dependence for all considered pairs, except for the Mexican peso-Brent. Our empirical results also show that the rise in the West Texas Intermediate (WTI) oil price returns is associated with a depreciation of the US dollar.

Linear time-varying regression with a DCC-GARCH model for volatility

ABSTRACT This article provides a new linear state space model with time-varying parameters for forecasting financial volatility. The volatility estimates obtained from the model by using the US stock market data almost exactly match the realized volatility. We further compare our model with traditional volatility models in the ex post volatility forecast evaluations. In particular, we use the superior predictive ability and the reality check for data snooping. Evidence can be found supporting that our simple but powerful regression model provides superior forecasts for volatility.

STRATEGIC BIDDING AND CONTRACT RENEGOTIATION

When firms bid in procurement auctions, they take into account the likelihood of future contract renegotiations. If they anticipate that certain input quantities will change ex post, they have an incentive to strategically skew their itemized bids, thereby increasing profits for themselves and costs for the procuring agency. We develop and estimate a structural model of strategic bidding using a data set of road construction projects in Vermont. We find that bidding strategies lead to increased markups for renegotiated items and reduced markups for nonrenegotiated items, results consistent with bid�?skewing.

The impact of regional competition on the health care industry

ABSTRACT We investigate factors that determine firm markups by employing data on prices and quantities of various medical procedures at major hospitals in the United States. We focus on the impact of hospital quality, rival competition and the number of medical procedures upon the health care demand. Our analysis covers health-care markets across the United States with the market definition based upon the hospital referral regions. Our findings highlight potential implications of the relationship between hospital markups and market structure.

Directional time-varying partial correlation with the Gaussian copula–DCC–GARCH model

ABSTRACT This article suggests a directional time-varying partial correlation based on the dynamic conditional correlation (DCC) method. A recent study proposed the copula DCC based on the vine structure. Due to the arbitrary variable selection, their method can produce unnecessary dependence in the multivariate structure, with extra economic and computational burdens. To overcome this limitation, we incorporate directional dependence by copula to track the causal relationship among multiple variables and then extend the copula bivariate DCC method to a directional time varying partial correlation in the multivariate structure. Our proposed method provides a reasonable and efficient conditional dependence structure, without the trial and error process. We offer an application of our method to the U.S. stock market as an illustrated example.

A new generalized volatility proxy via the stochastic volatility model

ABSTRACT This article proposes power transformation of absolute returns as a new proxy of latent volatility in the stochastic model. We generalize absolute returns as a proxy for volatility in that we place no restriction on the power of absolute returns. An empirical investigation on the bias, mean square error and relative bias is carried out for the proposed proxy. Simulation results show that the new estimator exhibiting negligible bias appears to be more efficient than the unbiased estimator with high variance.

Renegotiation on incomplete procurement contracts

ABSTRACT This article examines the impact of incomplete contracts on procurement costs in road construction auctions. Ex ante contracts in these auctions often fail to specify all of the potential construction contingencies, and consequently, changes in scope are necessary after construction begins. Using Vermont road construction contract data, this study finds evidence that there is a statistically significant difference in costs of firms between auctions with and without extra work adjustments. Substantial adaptation costs are responsible for the higher procurement outlays in incomplete contract. I also find that bidders inflate their bids to incorporate risk premiums in incomplete contracts; however, my estimates suggest that this bidding behaviour does not affect their profit margins.