The unrealized losses included $161 million related to a decline in the value of commercial real estate debt, said Zlatkus.
Zlatkus said Hartford Financial has seen little deterioration in subprime residential mortgage-backed securities.
Second quarter earnings dropped 13 percent for the life and property-casualty insurer, reflecting catastrophe claims and poor investment returns.
In the last few quarters, insurers in general have been buffeted by softening insurance rates. Lagging returns on investment are also troubling insurers, a result of the U.S. mortgage market crisis and wider credit market turmoil.