We propose a regression discontinuity design to determine whether
there is a difference in the expected returns of green versus brown secu-
rities (greenium). We analyze daily changes in option-implied expected
returns following the outcome of close vote ecology-related shareholder
proposals to estimate the causal impact of a small change in investors’
aggregate greenness perception on expected returns. Upon proposals’
passage, expected returns with a forecast horizon of 365 (730) days drop
by approximately 9.3% (6.9%) relative to proposals’ failure, indicating
the existence of a negative greenium in US equity markets. Our results
are robust to the introduction of a battery of fixed effects and when ac-
counting for multiple periods around shareholder proposal voting dates.