Gross Margin, LIFO and FIFO Gross Margin
We define gross margin as sales minus merchandise costs, including advertising, warehousing, and transportation. Rent expense, depreciation and amortization expense, and interest expense are not included in gross margin.
Our gross margin rate, as a percentage of sales, was 22.85% for the third quarter of 2024, compared to 22.03% for the third quarter of 2023. This increase in rate was achieved while maintaining competitive prices and helping customers manage their budgets. The increase in rate in the third quarter of 2024, compared to the third quarter of 2023, resulted primarily from the sale of our Kroger Specialty Pharmacy business, which has a lower gross margin rate, lower shrink, decreased fuel sales, which have a lower gross margin rate, strong Our Brands performance and a decreased LIFO charge, partially offset by lower pharmacy margins.
Our gross margin rate, as a percentage of sales, was 22.59% for the first three quarters of 2024, compared to 22.08% for the first three quarters of 2023. This increase in rate was achieved while maintaining competitive prices and helping customers manage their budgets. The increase in rate in the first three quarters of 2024, compared to the first three quarters of 2023, resulted primarily from strong Our Brands performance, decreased fuel sales, which have a lower gross margin rate, lower shrink, the sale of our Kroger Specialty Pharmacy business, which has a lower gross margin rate, our ability to effectively manage product costs through sourcing practices and a decreased LIFO charge, partially offset by lower pharmacy margins.
Our LIFO charge was $4 million in the third quarter of 2024, compared to $29 million in the third quarter of 2023. Our LIFO charge was $66 million in the first three quarters of 2024, compared to $131 million in the first three quarters of 2023. Our decreased LIFO charge for the first three quarters of 2024, compared to the first three quarters of 2023, was due to our lower expected annualized product cost inflation for 2024 compared to 2023.
Our FIFO gross margin rate, which excludes the LIFO charge, was 22.86% in the third quarter of 2024, compared to 22.11% in the third quarter of 2023. Our fuel sales lower our FIFO gross margin rate due to the very low FIFO gross margin rate, as a percentage of sales, of fuel sales compared to non-fuel sales. Excluding the effect of fuel, our FIFO gross margin rate increased 51 basis points in the third quarter of 2024, compared to the third quarter of 2023. This increase in rate was achieved while maintaining competitive prices and helping customers manage their budgets. This increase resulted primarily from the sale of our Kroger Specialty Pharmacy business, which has a lower gross margin rate, lower shrink and strong Our Brands performance, partially offset by lower pharmacy margins. Excluding the effect of fuel and Kroger Specialty Pharmacy, our FIFO gross margin rate increased 25 basis points in the third quarter of 2024, compared to the third quarter of 2023.
Our FIFO gross margin rate, which excludes the LIFO charge, was 22.65% in the first three quarters of 2024, compared to 22.19% in the first three quarters of 2023. Excluding the effect of fuel, our FIFO gross margin rate increased 25 basis points in the first three quarters of 2024, compared to the first three quarters of 2023. This increase in rate was achieved while maintaining competitive prices and helping customers manage their budgets. This increase resulted primarily from strong Our Brands performance, lower shrink, the sale of our Kroger Specialty Pharmacy business, which has a lower gross margin rate, our ability to effectively manage product costs through sourcing practices and a decreased LIFO charge, partially offset by lower pharmacy margins. Excluding the effect of fuel and Kroger Specialty Pharmacy, our FIFO gross margin rate increased 14 basis points in the first three quarters of 2024, compared to the first three quarters of 2023.
Operating, General and Administrative Expenses
OG&A expenses consist primarily of employee-related costs such as wages, healthcare benefit costs, retirement plan costs, utilities and credit card fees. Rent expense, depreciation and amortization expense, and interest expense are not included in OG&A.
OG&A expenses, as a percentage of sales, were 17.54% in the third quarter of 2024 and 16.63% in the third quarter of 2023. The increase in the third quarter of 2024, compared to the third quarter of 2023, resulted primarily from the 2024 Third Quarter OG&A Adjusted Item, the effect of decreased fuel sales, which increases our OG&A rate, as a percentage of sales, increased incentive plan costs and the sale of our Kroger Specialty Pharmacy business, which has a lower OG&A rate to sales, partially offset by continued execution of broad-based cost savings initiatives that drive administrative efficiencies, including store productivity and the 2023 Third Quarter OG&A Adjusted Item.