Worcester-based CNB Financial Corp., parent company of Commonwealth National Bank, has reported a net loss for the third quarter of $2.9 million, compared to net income of $92,000 for the comparable quarter in 2007, a $3 million negative swing.

The net loss for the first nine months of 2008 was $2.5 million, compared to net income of $232,000 for the same period of 2007.

The loss for the three and nine months ended Sept. 30 was due to a $3 million non-cash other-than-temporary impairment charge on investments in Fannie Mae and Freddie Mac preferred stock, which was previously disclosed by the company Sept. 8, according to the bank.