Interest and Other Income, net. Interest and other non-operating income, net, was $3.0 million for the three-months ended June 30, 2019, as compared to interest and other non-operating income, net, of $0.5 million for the three-months ended June 30, 2018. Foreign currency transaction losses were $0.9 million and $1.9 million for the three-months ended June 30, 2019 and 2018, respectively. Interest income was $4.1 million and $2.7 million for the three-months ended June 30, 2019 and 2018, respectively.
Provision for Income Taxes. Provision for income taxes was $89.5 million for the three-months ended June 30, 2019, an increase of $1.5 million, or 1.7% higher than the provision for income taxes of $88.0 million for the three-months ended June 30, 2018. The effective combined federal, state and foreign tax rate decreased to 23.4% from 24.6% for the three-months ended June 30, 2019 and 2018, respectively. The decrease in the effective tax rate was primarily attributable to the increase in profits earned by certain foreign subsidiaries in lower tax jurisdictions than the United States.
Net Income. Net income was $292.5 million for the three-months ended June 30, 2019, an increase of $22.4 million, or 8.3% higher than net income of $270.1 million for the three-months ended June 30, 2018. The increase in net income was primarily due to the $41.0 million increase in gross profit. The increase in net income was partially offset by the increase in operating expenses of $19.7 million.
Results of Operations for the Six-Months Ended June 30, 2019 Compared to the Six-Months Ended June 30, 2018.
Net Sales. Net sales were $2.05 billion for the six-months ended June 30, 2019, an increase of approximately $183.2 million, or 9.8% higher than net sales of $1.87 billion for the six-months ended June 30, 2018. Net sales for the six-months ended June 30, 2019 were positively impacted by approximately $59.5 million as a result of a price increase effective from November 1, 2018 in the United States and effective from February 1, 2019 in Canada, on certain of our Monster Energy® brand energy drinks. Net changes in foreign currency exchange rates had an unfavorable impact on net sales of approximately $47.9 million for the six-months ended June 30, 2019.
Net sales for the Monster Energy® Drinks segment were $1.89 billion for the six-months ended June 30, 2019, an increase of approximately $179.6 million, or 10.5% higher than net sales of $1.71 billion for the six-months ended June 30, 2018. Net sales for the Monster Energy® Drinks segment increased primarily due to (i) sales of our Reign Total Body FuelTM high performance energy drinks, introduced in the first quarter of 2019, and (ii) the price increase described above. Net changes in foreign currency exchange rates had an unfavorable impact on net sales for the Monster Energy® Drinks segment of approximately $40.3 million for the six-months ended June 30, 2019.
Net sales for the Strategic Brands segment were $149.4 million for the six-months ended June 30, 2019, an increase of approximately $3.9 million, or 2.7% higher than net sales of $145.6 million for the six-months ended June 30, 2018. Net changes in foreign currency exchange rates had an unfavorable impact on net sales for the Strategic Brands segment of approximately $7.6 million for the six-months ended June 30, 2019.
Net sales for the Other segment were $11.1 million for the six-months ended June 30, 2019, a decrease of approximately $0.2 million, or 1.5% lower than net sales of $11.3 million for the six-months ended June 30, 2018.
Case sales, in 192-ounce case equivalents, were 220.9 million cases for the six-months ended June 30, 2019, an increase of approximately 18.5 million cases or 9.2% higher than case sales of 202.4 million cases for the six-months ended June 30, 2018. The overall average net sales per case (excluding net sales of AFF Third-Party Products of $11.1 million and $11.3 million for the six-months ended June 30, 2019 and 2018, respectively, as these sales do not have unit case equivalents) increased to $9.23 for the six-months ended June 30, 2019, which was 0.7% higher than the average net sales per case of $9.17 for the six-months ended June 30, 2018. The increase in the average net sales per case was primarily attributable to a price increase effective from November 1, 2018 in the United States and effective from February 1, 2019 in Canada, on certain of our Monster Energy® brand energy drinks.
Gross Profit. Gross profit was $1.23 billion for the six-months ended June 30, 2019, an increase of approximately $99.3 million, or 8.7% higher than the gross profit of $1.14 billion for the six-months ended June 30, 2018. The increase in gross profit dollars was primarily the result of the $179.6 million increase in net sales of our Monster Energy® Drinks segment for the six-months ended June 30, 2019.