We continue to experience strong leasing demand both domestically and internationally. Amendments which were predominantly from AT&T, Verizon and Sprint continue to be numerous and contributed approximately 80% of US leasing revenue added in the quarter. The big four US carriers contributed approximately 0.75 of our consolidated incremental leasing activity in the quarter. We have a solid leasing backlog and expect that the third quarter will be another strong one in terms of customer activity. We are off to a good start in the quarter.
Our services revenues were $25.6 million compared to $20.9 million in the year earlier period. Services segment operating profit was $4.1 million in the second quarter compared to $2.9 million in the second quarter of 2011. Services segment operating profit margin was 16.1% compared to 13.9% in the year earlier period.
SG&A expenses for the second quarter were $17.7 million including non-cash compensation charges of $3.8 million. SG&A expenses were $15.7 million in the year earlier period including non-cash compensation charges of $3.1 million. As a percentage of revenue, SG&A declined 150 basis points compared to the second quarter of 2011 reflecting the efficiency by which we can materially add assets.
Adjusted EBITDA was $142.9 million or a 30.5% increase over the year earlier period. Adjusted EBITDA margin was 65.6% in the second quarter of 2012 up from 64.8% in the year earlier period, an 80 basis point increase.AFFO increased 46% to $95.3 compared to $65.2 million in the second quarter of 2011. AFFO per share increased an industry leading 34.5% to $0.78 compared to $0.58 in the second quarter of 2011. Net loss attributable to SBA Communications Corporation during the second quarter was $53.5 million compared to a net loss of $29.8 million in the year earlier period. Contributing to net loss in the second quarter were $15.8 million in acquisition related expenses primarily associated with the Mobilitie transaction and a $27.1 million charge related to the early retirement of a portion of our 8% and 8.25% senior notes. We expect to incur similar type of charge in the third quarter and an anticipated amount of approximately $23 million primarily in connection with the early retirement of our remaining 8% senior notes and the Mobilitie bridge loan. Read the rest of this transcript for free on seekingalpha.com