Ahead of the Bell: Analyst downgrades Nymagic

Keefe, Bruyette & Woods Inc. analyst Dean Evans downgraded the New York-based company to "Underperform" from "Market Perform." The downgrade was based on "pre-announced investment and Gustav losses," Evans wrote in a research note to clients.

Nymagic's property and casualty insurance subsidiaries specialize in writing ocean marine, inland marine and non-marine liability insurance.

During August, Nymagic said it incurred additional realized and unrealized investment losses of approximately $7 million on its preferred stocks, exchange traded funds and mortgage backed securities.

Earlier this month, the company said net losses from its Gulf of Mexico platform and drilling vessel exposures attributable to Hurricane Gustav, if any, may be in the order of magnitude of $1 million.