Our consolidated OCF margins 10 for the three and nine months ended September 30, 2012 were 48.6% and 47.7%, respectively. These margins reflect year-over-year improvements of 50 and 10 basis points, respectively, over the corresponding prior year periods. The margin improvement in each period was aided by the consolidation of Kabel BW in 2012, offset in part by our Chilean mobile operations. As compared to our Q2 2012 OCF margin, our Q3 OCF margin was higher by 130 basis points with notable improvement evident in our western European operations. Collectively, our western European operations achieved an OCF margin of 56.6%, reflecting a 140 basis point improvement over Q2 levels.
For the three and nine months ended September 30, 2012, our reported operating income increased by 5% for both periods to $509 million and $1.5 billion, respectively, as compared to the respective prior year periods. The increase in each period was largely due to higher revenue and lower operating expenses measured as a percentage of revenue. These factors were partially offset by increases in our depreciation and amortization expense.
Net Earnings/Loss Attributable to LGI StockholdersWe reported a net loss attributable to LGI stockholders (“Net Loss”) of $22 million or $0.08 per basic and diluted share for the three months ended September 30, 2012. This compares to a Net Loss of $333 million or $1.18 per basic and diluted share for the respective 2011 period. The year-over-year improvement in our Net Loss, among other factors, resulted from an improvement in our foreign currency transaction results that were only partially offset by changes in the mark-to-market adjustments of our derivative instruments. On a year-to-date basis, we reported net earnings attributable to LGI stockholders (“Net Earnings”) of $654 million or $2.43 per basic and diluted share for the nine months ended September 30, 2012, versus a Net Loss of $338 million or $1.30 per basic and diluted share for the corresponding 2011 period. Our Net Earnings for the nine-month period reflects the positive impact of a $924 million gain on the disposition of our Austar interest in the second quarter of 2012.