Hartford Financial Services Group Inc. said it will cut 500 jobs, or about 2 percent, of its total work force this month, citing losses in its investment portfolios and declining revenue.

The Hartford, Conn.-based insurer said Tuesday the layoffs were announced internally on Monday. It employs about 31,000 people.

After reporting disappointing third-quarter results last week, the company said it would slash jobs and other expenses to save $250 million in annual costs by the end of 2009.

The company reported a loss of $2.6 billion, or $8.74 per share, compared with a profit of $851 million, or $2.68 per share, a year ago.

The news sent Hartford Financial's shares plummeting 58 percent during the week to close at $10.32. Shares fell as low as $8.23 during the week.

Its stock rebounded Monday, closing up 57.8 percent to $16.28.

Spokeswoman Shannon Lapierre said 500 employees around the country — including nearly 125 in the Hartford region — in life and property-casualty insurance operations and corporate staff will be notified by the end of this month that they will be laid off. No layoffs will take place in December, she said.