Third quarter 2011 gross margin was 30.1% compared to the 29.3% gross margin recognized during the same period in 2010.
Selling, general and administrative expenses totaled $17.0 million for the three months ended September 30, 2011 compared to $14.7 million during the same period in 2010, an increase of 15.6%. Selling, general and administrative expenses were, as a percentage of revenues, 19.7% for the quarter ended September 30, 2011 and 21.0% for the same period a year ago.
Operating income was $7.5 million for the third quarter of 2011 compared to $4.5 million in the second quarter of 2011 and $3.7 million in the year-ago period, an increase of 66.7% and 102.7%, respectively.
In the third quarter of 2011, the Company generated net income attributable to common stockholders, subsequent to dividends on preferred shares, of $3.6 million, or $0.17 per basic and $0.16 per diluted share, compared to net income attributable to common stockholders of $760,000, or $0.08 per basic and $0.06 per diluted share in the year-ago period.Adjusted EBITDA, a non-GAAP measure, was $9.4 million for the third quarter of 2011 compared to $6.0 million in the year-ago period, an increase of 56.1%. The Company maintains a revolving lease facility for the vehicles used in its daily operations. These leases are required to be treated as an operating lease for purposes of GAAP. Certain peers in our sector may have vehicle leases that qualify for capital lease treatment for GAAP purposes. Accordingly, the vehicle lease payments made of approximately $3.0 million and $2.5 million during the three months ended September 30, 2011 and 2010, respectively, would need to be added back to the adjusted EBITDA figures above in order to be comparable to a company whose vehicle leases are accounted for as capital leases. If these lease payments were added back, our adjusted EBITDA would be $12.4 million and $8.5 million for the three months ended September 30, 2011 and 2010, respectively.