retention. As a percentage of sales, selling, general and administrative expenses for the three months ended September 30, 2023 decreased to 7.0% from 7.1% in the comparable period in 2022.
Interest expense, net increased to $1,813 from $1,042 for the three months ended September 30, 2023 as compared to the prior year period. Increases in interest expense, net was primarily due to increases in floor plan interest payments, increased borrowings on our credit facility and increased interest rates.
For the three months ended September 30, 2023 the Company recognized a net foreign currency exchange loss of $17, compared to a net loss of $633 for the three months ended September 30, 2022, reflecting foreign currency gains and loss on transactions denominated in a currency other than the local entity’s functional currency.
The provision for income taxes for the three months ended September 30, 2023 and 2022 reflects a combined effective U.S. federal, state and foreign tax rate of 20.8% and 23.0%, respectively. The principal differences between the federal statutory tax rate and the effective tax rate consist primarily of state taxes, domestic tax credits, and tax differences on foreign earnings.
Results of Operations – Nine Months Ended September 30, 2023 Compared to Nine Months Ended September 30, 2022
Net sales for the nine months ended September 30, 2023 increased 37.7% to $857,108 from $622,602 for the comparable period in 2022. The increase in revenue is primarily the result of increases in production volume across all our product categories due to supply chain improvements and continued strong customer demand, as well as realization of pricing adjustments implemented in 2022 and the first quarter of 2023. Net domestic sales increased during the nine months ended September 30, 2023 to $773,189 from $562,235 for the comparable period in 2022, while net foreign sales increased to $83,919 from $60,367 during the same nine-month period.
Costs of operations for the nine months ended September 30, 2023 increased 31.5% to $743,894 from $565,708 for the comparable period in 2022, due to increased deliveries. Costs of operations decreased as a percentage of sales to 86.8%, compared to 90.9% for the comparable period in 2022, primarily due to the recognition of price increases on sales to customers that offset higher input costs, as well as enhanced operational efficiencies.
Selling, general and administrative expenses for the nine months ended September 30, 2023 increased to $56,721 from $39,710 for the comparable period in 2022 due to additional executive compensation expense as discussed in the 8-K filed in April 2023, investor relations activity, increased expenses associated with increased sales volumes and increased investment in our workforce, specifically for training and more competitive compensation to improve employee retention. As a percentage of sales, selling, general and administrative expenses for the nine months ended September 30, 2023 increased to 6.6% from 6.4% in the comparable period in 2022.
Interest expense, net increased to $4,525 from $2,088 for the nine months ended September 30, 2023 as compared to the prior year period. Increases in interest expense, net were primarily due to increased borrowings on our credit facility, increased interest rates and increases in floor plan interest payments.
For the nine months ended September 30, 2023 the Company recognized a net foreign currency exchange gain of $594, compared to a net loss of $1,097 for the nine months ended September 30, 2022, reflecting foreign currency gains and losses on transactions denominated in a currency other than the local entity’s functional currency.
The provision for income taxes for the nine months ended September 30, 2023 and 2022 reflects a combined effective U.S. federal, state and foreign tax rate of 21.2% and 21.6%, respectively. The lower year over year rate was due to favorable tax adjustments related to prior year domestic tax estimates. The principal differences between the federal statutory tax rate and the effective tax rate consist primarily of state taxes, domestic tax credits, and tax differences on foreign earnings.
Liquidity and Capital Resources
Cash provided by operating activities was $4,213 for the nine months ended September 30, 2023, compared to cash used in operating activities of $31,602 in the comparable period in 2022. Cash provided by or used in operating activities is generally attributable to the receipt of payments from our customers as settlement of their contractual obligation once we have fulfilled all performance obligations related to our contracts with them. These cash receipts are netted with payments for purchases of inventory, materials used in manufacturing, and other expenses that are necessary in the ordinary course of our operations, such as utilities and taxes. The change in net cash flows from operating activities during the nine months ended September 30, 2023, in comparison to the nine months ended September 30, 2022, is primarily due to increased net income and a stabilization of changes in operating assets and liabilities as a result of improved availability of purchased components.