Edison International on Thursday reported a lower second quarter profit, although a tax benefit boosted the year-earlier quarter.

The Rosemead parent of Southern California Edison reported net income of $176 million (54 cents per share), compared with $344 million ($1.05) in the same period a year earlier. The 2010 quarter was helped by a 43 cents-per-share gain related to a tax settlement. Analysts on average expected per-share profit of 50 cents.

Operating revenue rose 9.5 percent to $3 billion on rate base growth at SoCal Edison.

Wholesale generation revenue rose 8.7 percent, but the Edison Mission Group swung to a 9 cent per share loss due to lower realized energy prices, higher plant maintenance and outage costs.

SoCal Edison’s basic earnings were 65 cents per share compared to 92 cents a year earlier, when the unit benefited from a change in tax accounting primarily related to its infrastructure replacement program.

Edison reaffirmed its full-year core earnings guidance of $2.60 to $2.90 per share. “Our second quarter and year-to-date earnings performance is fully consistent with our 2011 earnings guidance, and we now see full-year 2011 earnings at the high end of our range,” Chief Executive Ted Craver said in a statement.

Shares closed down $1.83 cents, or 5 percent on the New York Stock Exchange.