increased $11.1 million or 119.4%, from the comparable period in 2019. Of this increase, $10.0 million relates to the mortgage division. Full-time equivalent employees, particularly in the mortgage division, increased from the prior year comparable quarter as we expanded our mortgage division into Maryland with the hiring of nearly 90 individuals since the first quarter of 2020. The number of full time employees at Meridian, particularly in SBA and lease lending, also increased over this period.
Loan expenses increased $300 thousand or 156.3%, from the comparable period in 2019, reflecting the higher levels of loan originations. Occupancy expense increased $162 thousand or 17.1%, from the third quarter of 2019 as the result of rent expense incurred at loan production locations for our mortgage division expansion into Maryland. Advertising and promotion expense increased $207 thousand, or 36.1%, from the comparable period in 2019. This increase was due to an increase in the number and length of advertising campaigns in addition to an increase in marketing costs for the mortgage division. Data processing costs increased $117 thousand or 34.2%, from the third quarter of 2019 as the result of increased loan processing activity from our mortgage division, combined with processing activity relating to PPP loans. Professional fees decreased $139 thousand or 17.0% due to a decline in legal and consulting expenses. Other expenses were up $367 thousand or 43.2%, as information technology related costs increased $60 thousand, insurance costs increased $226 thousand, combined with an increase of $126 thousand in various other expenses.
Nine Months Ended September 30, 2020 Compared to the Same Period in 2019
Total non-interest expense for the nine months ended September 30, 2020 was $61.2 million, up $22.2 million or 56.9%, from the nine months ended September 30, 2019. The increase is largely attributable to the variable expenses from loan originations overall, particularly mortgage commissions. Total salaries and employee benefits expense was $46.5 million, an increase of $20.7 million or 80.4%, compared to the nine months ended September 30, 2019. Of this increase, $18.9 million relates to the mortgage division. Full-time equivalent employees, particularly in the mortgage division, increased year-over-year. As noted above, in the first quarter of 2020, we expanded our mortgage division into Maryland with the hiring of nearly 90 individuals year to date.
Loan expenses increased by $628 thousand or 133.1% for the nine months ended September 30, 2020, reflecting the higher levels of commercial and consumer loan originations during the current year. Advertising expenses increased by $227 thousand or 12.8% during the nine months ended September 30, 2020, due mainly to an increase in marketing related costs from the mortgage division. Professional fees increased $118 thousand or 5.9%, compared to the prior year period due to an increase in consulting costs for bank-wide projects, partially offset by a decrease in certain audit related fees and external legal costs.
INCOME TAXES
Income tax expense for the three months ended September 30, 2020 was $2.8 million, as compared to $914 thousand for the same period in 2019. The increase in income tax expense was attributable to the increase in earnings, period over period. Our effective tax rate was 23.1% for the third quarter of 2020 and 21.6% for the third quarter of 2019.
Income tax expense for the nine months ended September 30, 2020 was $5.2 million, as compared to $2.1 million for the same period in 2019. The increase in income tax expense was attributable to the increase in earnings, period over period. Our effective tax rate was 23.0% for the first nine months of 2020 and 22.0% for the first nine months of 2019.
BALANCE SHEET ANALYSIS
As of September 30, 2020, total assets were $1.8 billion compared with $1.2 billion as of December 31, 2019 and $1.1 billion as of September 30, 2019. Total assets increased $608.6 million, or 52.9%, from December 31, 2019 and $631.7 million, or 56.1%, from September 30, 2019, primarily due to strong loan growth.
Total loans, excluding mortgage loans held-for-sale, grew $342.1 million, or 35.5%, to $1.3 billion as of September 30, 2020, from $964.7 million as of December 31, 2019 and $371.0 million or 39.6% from $935.9 million as of September 30, 2019. The increase in loans for both periods is attributable largely to the $260 million in PPP loans granted to borrowers during the nine months ended September 30, 2020. There was also growth in several commercial categories as we continue