Cost of Sales (Excluding Depreciation and Amortization)
Cost of sales, excluding depreciation and amortization, was $2,425 million and $2,512 million for the three months ended September 30, 2024 and 2023, respectively, and $7,065 million and $7,450 million for the nine months ended September 30, 2024 and 2023, respectively. These amounts represented 79 percent and 81 percent of consolidated net sales for the three months ended September 30, 2024 and 2023, respectively, and 79 percent and 81 percent of consolidated net sales for the nine months ended September 30, 2024 and 2023, respectively. The decrease for the three months ended September 30, 2024, was primarily due to lower manufacturing costs, including lower aluminum costs of $41 million, and other items discussed in the reportable segment sections below. The decrease for the nine months ended September 30, 2024, was primarily due to lower manufacturing costs, including lower aluminum costs of $269 million and lower freight costs of $53 million, and other items discussed in the reportable segment sections below.
Depreciation and Amortization
Depreciation and amortization expense was $150 million and $152 million for the three months ended September 30, 2024 and 2023, respectively, and $460 million and $449 million for the nine months ended September 30, 2024 and 2023, respectively. These amounts represented 5 percent of consolidated net sales for the three and nine months ended September 30, 2024 and 2023. The increase for the nine months ended September 30, 2024, was primarily due to the company’s larger depreciable asset base.
Selling, General and Administrative
Selling, general and administrative was $142 million and $133 million for the three months ended September 30, 2024 and 2023, respectively, and $518 million and $409 million for the nine months ended September 30, 2024 and 2023, respectively. These amounts represented 5 percent and 4 percent of consolidated net sales for the three months ended September 30, 2024 and 2023, respectively, and 6 percent and 4 percent of consolidated net sales for the nine months ended September 30, 2024 and 2023, respectively. The increase for the nine months ended September 30, 2024, was primarily due to increased compensation costs of $98 million, including incremental compensation cost from the successful sale of the aerospace business consisting of cash bonuses and stock based compensation.
Business Consolidation and Other Activities
Business consolidation and other activities resulted in charges of $85 million and $29 million for the three months ended September 30, 2024 and 2023, respectively, and charges of $171 million and $43 million for the nine months ended September 30, 2024 and 2023, respectively. The amounts in 2024 and 2023 primarily included facility shutdown costs. Further details regarding business consolidation and other activities are provided in Note 6.
Interest Income
Interest income was $14 million and $12 million for the three months ended September 30, 2024 and 2023, respectively, and $58 million and $23 million for the nine months ended September 30, 2024 and 2023, respectively. The increases in interest income for the three and nine months ended September 30, 2024, were primarily due to the higher amount of cash on hand in 2024 from the aerospace sale.
Interest Expense
Interest expense was $67 million and $122 million for the three months ended September 30, 2024 and 2023, respectively, and $228 million and $351 million for the nine months ended September 30, 2024 and 2023, respectively. Interest expense as a percentage of average borrowings decreased by approximately 50 basis points from 5.1 percent for the three months ended September 30, 2023, to 4.6 percent for the three months ended September 30, 2024, and remained constant at 4.9 percent for the nine months ended September 30, 2024 and 2023. The interest expense decrease for the three months ended September 30, 2024, was primarily driven by a decrease of $29 million from a smaller amount of weighted average principal outstanding during the quarter, resulting mainly from the use of proceeds from the aerospace disposal, and a decrease of $26 million from lower weighted average interest rates on outstanding debt during the quarter. The interest expense decrease for the nine months ended September 30, 2024, was driven by a smaller amount of weighted average principal outstanding during the year, resulting mainly from the use of proceeds from the