Net interest income for the fourth quarter of 2012 increased 16.9% to $41.3 million from $35.3 million during the fourth quarter of 2011. For the fourth quarter of 2012, the effective yield on non-covered loans and covered loans was 6.03% and 7.83%, respectively. Net interest margin, on a fully taxable equivalent basis, was 4.86% for the quarter just ended compared to 4.73% in the fourth quarter of 2011, an increase of 13 basis points. The Company's ability to improve pricing on interest bearing deposits and hold the changes of interest rates on loans to a minimum allowed the Company to improve net interest margin.
The Company reported $16.2 million of non-interest income for the fourth quarter of 2012, compared to $12.2 million for the fourth quarter of 2011. The most important components of the fourth quarter non-interest income were $5.2 million from gain on acquisition, $4.1 million from service charges on deposits accounts, $3.1 million from other service charges and fees, $1.5 million from mortgage lending income, $635,000 in dividends, $368,000 from insurance commissions, $229,000 of accretion on the FDIC indemnification asset and $121,000 gain on sale of OREO. The $635,000 in dividends includes a non-recurring dividend of approximately $463,000 from our investment in a private equity and venture capital firm which invests in small and lower middle market companies located in Arkansas and across the Midwest and Southeast United States.
Non-interest expense for the fourth quarter of 2012 was $29.6 million compared to $23.3 million for the fourth quarter of 2011. Excluding merger expenses, non-interest expense only increased 5.5% when compared to 17.7% in asset growth. For the fourth quarter of 2012, our core efficiency ratio was 44.40% or improved by 436 basis points from the same period of the previous year.Financial Condition Total non-covered loans were $2.33 billion at December 31, 2012 compared to $1.76 billion at December 31, 2011. Total covered loans were $384.9 million at December 31, 2012 compared to $481.7 million at December 31, 2011. Total deposits were $3.48 billion at December 31, 2012 compared to $2.86 billion at December 31, 2011. Total assets were $4.24 billion at December 31, 2012 compared to $3.60 billion at December 31, 2011.