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THE IMPACT OF AIR POLLUTION EMISSIONS AND RELATED HUMAN HEALTH RISKS ON THE CROSS-SECTION OF STOCK RETURNS. Dinah A. Koehler EPA Bernell K. Stone BYU. CONCERN. For a cross section of companies/industries, does air pollution, especially health damaging air pollution,
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THE IMPACT OF AIR POLLUTION EMISSIONS AND RELATEDHUMAN HEALTH RISKS ON THECROSS-SECTION OF STOCK RETURNS Dinah A. Koehler EPA Bernell K. Stone BYU
CONCERN For a cross section of companies/industries, does air pollution, especially health damaging air pollution, have a systematic effect on valuation?
HYPOTHESES Null: no effect Alternative l: Positive effect, i.e.: More pollution greater value Alternative 2: Negative effect, i.e.: More pollution lower value
HYPOTHESES Null Positive Negative • Comments: • In equilibrium, value and return realization are inversely related. • Revaluation from new information and/or from changes in how stocks are valued can be source of noise, possibly distortion.
ASSESSMENT ISSUES • Fair return for time and risk • Other cross-sectional return dependency variables • Interpretative complexities
FAIR RETURN MODELS CAPM (Capital Asset Pricing Model) 2 return factors: - time (short-term riskless interest rate) - systematic market risk (beta) Rs = Rf + (RM - Rf)βs Multifactor - Endogenous Factors (APT) - Exogenous Factors (specified variables) Example: “Fama-French 3 Factor”
OTHER CROSS SECTIONAL RETURN DEPENDENCY VARIABLES • Other so-called anomaly variables • Taxes and financial structure • Growth, profitability, and other performance attributes • Industry
INTERPRETATIVE COMPLEXITIES The usual specification problems • Measurement error • Omitted variables • Improperly specified functional dependencies • Correlation distortion State of the economy State of the market • Changing level of interest rates • Changing term structure • Changing currency values • Hot and cold styles (e.g., growth vs value) Industry-specific effects Arrival of new value changing information
STUDY LOGIC DATA • Rank Order into Industry Portfolios • Step-Wise use of MAP Scatter Plots Regression Fits Hypothesis Tests
STUDY LOGIC DATA • Rank Order into Industry Portfolios • Step-Wise use of MAP • Model 1: No control restrictions • Model 2: CAPM beta • Model 3: Fama-French 3-Factor • Model 4: 7-Factors: EY, DY, FS, ET • Model 5: Add Growth and Profitability
STUDY LOGIC DATA • Rank Order into Industry Portfolios • Step-Wise use of MAP Scatter Plots Regression Fits Hypothesis Tests
Linear Regression Results: 1998-2002 * p < .01 ** p < .001
Linear Regression Results: 1998-2002 * p < .01 ** p < .001
MAJOR CONCLUSIONS • Tonnage of air pollution is not significant • Cancer health risk is significant • Lung health risk is significant
INTERPRETATIVE COMPLEXITY:EQUILIBRIUM VS REVALUATION “Equilibrium” (no pollution-related revaluation) -market failure in that companies in industry groups producing more health damaging air pollution are more highly valued than otherwise identical companies -there is a need for pertinent regulation Cross-time revaluation -the market believes that there is the possibility that health-related air pollution will be more regulated (with costs to the polluting companies), and/or -the market becomes concerned with health-related legal liability (as occurred for asbestos and tobacco)
METHODOLGY CONCLUSIONS Many variable impacts For pollution, it is crucial to control for • Fair return for time and risk • Taxes and financial structure • Growth and profitability • Industry attributes
ON-GOING AND FUTURE RESEARCH Size scaling alternatives Outlier control Industry impacts/distortion More portfolios per cross-section More sensitivity analysis Additional years?