Shares in Santa Monica-based Anworth Mortgage Asset Corp. edged up Thursday as the company swung to a quarterly net loss due to losses in its mortgage portfolio and a charge on discontinued operations.

Anworth reported a third quarter net loss of $158.5 million ($3.47 per share) compared to a loss of $3.4 million (7 cents) for the same period a year earlier. This represents the first quarterly loss for 2007 for Anworth; during the second quarter, the company reported $2.1 million in net income.

The company said the third quarter loss included a loss of $23.4 million from the sale of approximately $904 million of mortgage-backed securities and a loss of $136.7 million due to losses on sales and a charge on the assets of the discontinued Belvedere Trust Mortgage Corp.

Revenues for the real estate investment trust were in the form of interest income and totaled $62.1 million for the third quarter, up from $55.3 million for the same period a year earlier.

The third quarter loss was below the consensus analyst estimate of $2.17 per share.

Anworth shares closed Thursday at $7.10 per share, up $0.11 or 1.6 percent for the day.