Revenue during the fourth quarter increased 12.9% to $203.1 million versus $180 million a year ago, driven by broad-based demand across our portfolio.
Quarterly gross profits increased by 21.6% year-over-year to $26.9 million and our gross margin expanded 100 basis points year-over-year to 13.3%, which reflects strong demand, favorable mix and other cost reduction measures.
Additionally, during the quarter we continue to realize benefits from our cost control initiatives as SG&A expenses as a percentage of sales decreased by approximately 20 basis points from the prior year period.
Net income was $11.7 million or $1.03 per share compared to net income of $10.8 million or $0.95 per share in the fourth quarter of 2018.
Net sales for the fourth quarter 2019 were $203.1 million versus $180 million for the fourth quarter of 2018, a 12.9% year-over-year increase driven by broad-based demand across our portfolio, as well as some additional sales that were included in the fourth quarter as a result of supplier delay issues we experienced in the preceding quarter.
Cost of operations increased 11.7% to $176.2 million for the fourth quarter 2019 compared to $157.8 million for the fourth quarter 2018, driven by our top line sales growth.
However, cost of operations as a percentage of net sales contracted approximately 100 basis points to 86.7% from the prior year period.
Gross profit was $26.9 million or 13.3% of net sales for the fourth quarter 2019 compared to $22.2 million or 12.3% of net sales for the fourth quarter 2018, reflecting a favorable product mix.
SG&A expenses were $11.8 million for the fourth quarter 2019 compared to $10.8 million for the fourth quarter 2018.
As a percentage of sales, SG&A decreased approximately 20 basis points to 5.8% from 6% in the prior year period, driven by our effective cost controls and increased operational efficiency across the organization.
Interest expense, net, for the fourth quarter 2019 was $565,000 compared to $449,000 for the fourth quarter 2018, as an increase in customer floor plan financing cost more than offset lower long-term debt-related interest expense.
Other income expense for the fourth quarter 2019 was a net gain of $211,000 compared to a net expense of $465,000 for the fourth quarter 2018, due primarily to currency exchange rate fluctuations.
Net income for the fourth quarter 2019 was $11.7 million or $1.03 per diluted share.
Net income for the fourth quarter 2018 was $10.8 million or $0.95 per diluted share.
Now, let me briefly review our results for the 12 months ended December 31, 2019.
Net sales for the year were $818.2 million compared to $711.7 million in the prior year period, an increase of 15%.
Gross profit for the year was $96.5 million or 11.8% of net sales compared to $83.3 million or 11.7% of net sales for 2018.
SG&A expenses were $43.4 million for 2019 or 5.3% of net sales compared to $39.5 million or 5.6% of net sales for 2018.
Net income for the year was $39.1 million or $3.43 per diluted share, an increase of 15.9% compared to net income of $33.7 million or $2.96 per diluted share in 2018.
Cash and cash equivalents as of December 31, 2019 was $26.1 million compared to $27.5 million as of September 30, 2019 and $27 million at December 31, 2018.
Accounts receivable at December 31, 2019 totaled $168.6 million compared to $165.8 million as of September 30, 2019 and $149.1 million at December 31, 2018.
Inventories were $88 million as of December 31, 2019, compared to $98.1 million as of September 30, 2019 and $93.8 million at December 31, 2018.
Accounts payable at December 31, 2019 was $95.8 million compared to $114.9 million as of September 30, 2019 and $98.2 million at December 31, 2018.
During the quarter, we reduced our long-term debt by approximately $5 million from the prior quarter, bringing the balance to approximately $5 million as of December 31, 2019.
Lastly, the Company also announced that its Board of Directors approved our quarterly cash dividend of $0.18 per share payable March 23, 2020 to shareholders of record at the close of business on March 16, 2020.
Our quarterly dividend of $0.18 per share underscores our continued commitment to returning capital to our shareholders.
Leigh Walton is an independent director and she has more than 40 years of experience, advising public companies on -- in the areas of corporate governance and corporate finance.
In addition, I'd like to just take one second to congratulate all the employees at Miller Industries and all of our vendors, suppliers and other partners, distributors for a phenomenal year, a record-breaking year after 30 years of $818 million in sales.

Summary:
Revenue during the fourth quarter increased 12.9% to $203.1 million versus $180 million a year ago, driven by broad-based demand across our portfolio.
Net income was $11.7 million or $1.03 per share compared to net income of $10.8 million or $0.95 per share in the fourth quarter of 2018.
Net sales for the fourth quarter 2019 were $203.1 million versus $180 million for the fourth quarter of 2018, a 12.9% year-over-year increase driven by broad-based demand across our portfolio, as well as some additional sales that were included in the fourth quarter as a result of supplier delay issues we experienced in the preceding quarter.
Net income for the fourth quarter 2019 was $11.7 million or $1.03 per diluted share.