Mr. Cornelsen said, "We continue to make significant progress towards our goal of becoming the premier community bank in the Metro Washington, D.C. market. As we have grown the assets and the branches of the organization, through acquisition and organic growth, we have consistently maintained stellar asset quality indicators while improving annual profitability. Since the acquisition of Maryland Bankcorp, we have successfully disposed of troubled assets and have grown our loan and deposit base. Our future appears bright and I believe that with the acquisition of WSB Holdings, Inc. that we expect to complete during the second quarter of 2013 that we will continue to enhance Old Line Bank's franchise value in the years ahead."
The 39.97% increase in net income available to common stockholders was primarily the result of a $6.1 million increase in net interest income. This increase derived from the $142.6 million or 23.78% growth in average interest earning assets and a modest increase in the net interest margin from 4.61% for the period ending December 31, 2011 compared to 4.65% for the period ending December 31, 2012, while at the same time total interest expense decreased approximately $162,000 for the twelve months ended December 31, 2012 compared to the same period in 2011. The increase in average interest earning assets was the result of a $108.6 million increase in average gross loans and an approximately $35.0 million increase in average invested funds. The primary cause of this growth was the acquisition of Maryland Bankcorp, Inc. on April 1, 2011 coupled with organic growth of approximately $55.0 million during 2012. This growth and an approximately $1.2 million increase in the accretion of fair value adjustments that were recorded in conjunction with the merger, were the predominant causes of the increase in net interest income.
Non-interest revenue also increased $1.1 million during the twelve months primarily as a result of a $1.0 million increase in gains on sales of investment securities, a $155,501 increase in other fees and commissions and a $72,721 increase in service charges on deposit accounts. During 2011, we also incurred an other than temporary impairment on securities of $123,039 that we did not incur in 2012. These increases were partially offset by a $153,055 decrease in earnings on bank owned life insurance and a $137,301 decline in gains on sales of other real estate owned.