This study attempts to resolve two important issues. First, it investigates the diversification benefit of crude oil for equities. Second, it examines whether or not crude oil derivatives transactions by oil and gas producers can change shareholders' wealth. With these two major goals in mind, I study the risk and return profile of crude oil, the value effect of crude oil derivatives transactions, and the systematic risk exposure effect of crude oil derivatives transactions. In contrast with previous studies, this study applies the Goldman Sachs Commodity Index (GSCI) methodology to measure the risk and return profile of crude oil. The results show that crude oil is negatively correlated with stocks so adding crude oil into a portfolio with equities can provide significant diversification benefits for the portfolio. Given the diversification benefit of crude oil mixed with equities, this study then examines the value effect of crude oil derivatives transactions by oil and gas producers. Differing from traditional corporate risk management literature, this study examines corporate derivatives transactions from the shareholders' portfolio perspective. The results show that crude oil derivatives transactions by oil and gas producers do impact value. If oil and gas producing companies stop shorting crude oil derivatives contracts, …