"The immediate disruptions of these disasters tend to cause short-term liquidity problems," Moody's said, "but subsequent spending from insurance, federal aid, state support and private charitable donations is very stimulative for local and regional economies. " The Moody's report followed one published Wednesday by Standard & Poor's. In that report, Standard & Poor's said it "does not expect to see deterioration in investment-grade credits" if there are short-term service interruptions and issuers have business interruption insurance or are eligible for Federal Emergency Management Agency reimbursements. However, Standard & Poor's said it is monitoring credits that have been affected by Hurricane Sandy and could revise its views. If the revenue-generating capacity of an issuer or borrower is "materially impaired for an extended period, credit quality could be pressured," the rating agency said.