We exploit two regulatory shocks to examine the informational effects of tightening preexisting mandatory disclosure rules. Canadian National Instrument 51‐101 in 2003 and the U.S. rule “Modernization of Oil and Gas Reporting” in 2009 introduced quasi‐identical amendments which effectively tightened the rules governing oil and gas reserve disclosures in both countries. We document significant changes in firms' reporting outcomes when the new regulations are introduced. We also find that the reserve disclosures filed under the new regulations are more closely associated with stock price changes and with decreases in bid‐ask spreads. Our findings are robust to controlling for other confounding factors such as time trends, other information disclosed simultaneously, financial reporting incentives, mispricing, and monitoring efforts.

The question we address is whether mandated disclosure about dispersion of nonfinancial asset values can provide information relevant to assessing firm risk. Using a sample of Canadian oil and gas (O&G) firms between 2004 and 2011, we find that the difference between the disclosed 10th and 50th percentiles from the O&G reserves distribution, which measures dispersion of the distribution, is positively associated with future total and idiosyncratic equity return volatility, systematic risk, and credit risk. We also find that disclosure of increased reserves dispersion is associated with weaker stock price reactions to increases in reserves and with increases in bid-ask spreads, both of which indicate the disclosures convey information about risk associated with reserves. Additional tests reveal little evidence of managerial opportunism in the reserves disclosures. Taken together, our evidence suggests that quantitative disclosures about the dispersion of nonfinancial asset values can provide information relevant to assessing firm risk.