Participants

Timothy Fitzgerald; President and Chief Financial Officer; NewMarket Corp

Presentation

Operator

Good day, everyone, and welcome to the NewMarket Corporation's scheduled conference call and webcast to review the fourth-quarter 2024 financial results. At this time, all participants have been placed on a listen-only mode.
It is now my pleasure to turn the floor over to your host, Tim Fitzgerald. Sir, the floor is yours.

Timothy Fitzgerald

Thank you, Matthew, and thanks to everyone for joining me this afternoon.
As a reminder, some of the statements made during this conference call may be forward-looking. Relevant factors that could cause actual results to differ materially from those forward-looking statements are contained in our earnings release and in our SEC filings, including our most recent Form 10-K. During this call, we will also discuss the non-GAAP financial measures included in our earnings release. The earnings release, which can be found on our website, includes a reconciliation of the non-GAAP financial measures to the comparable GAAP financial measures. We intend to file our 2024 10-K in the middle of February. It will contain significantly more details on the operations and performance of our company. Today, I will be referring to the data that was included in last night's release.
Net income for the fourth quarter of 2024 was $111 million or $11.56 per share compared to net income of $80 million or $8.38 per share for the fourth quarter of 2023. Net income for the full-year 2024 was $462 million or $48.22 per share compared to net income of $389 million or $40.44 per share for 2023. Petroleum additive sales for the fourth quarter of 2024 were $626 million compared to $642 million for the same period in 2023. Petroleum additives operating profit for the fourth quarter of 2024 was $136 million compared to $110 million for the fourth quarter of 2023.
The increase in operating profit was mainly due to lower operating costs. We continue to focus on operational efficiency while still making investments in technology to support our customers. These gains were partially offset by a decrease in shipments as customers managed year-end inventory levels.
For the full-year 2024, sales for the petroleum additive segment were $2.6 billion compared to $2.7 billion in 2023. Petroleum additives operating profit for 2024 was $592 million compared to $514 million for 2023. The increase in operating profit was a result of lower operating costs driven by our efficiency efforts as well as lower raw material costs offset by lower selling prices. Shipments were flat when comparing 2024 to 2023 with a small increase in lubricant additives offset by a decline in fuel additives.
We are very pleased with the performance of our petroleum additives business during 2024 and the work done by our team to achieve four quarters of strong operating profit. However, we remain challenged by the ongoing inflationary environment despite our efforts to improve efficiency and manage our operating costs. We continue to focus on investing in technology to meet customer needs, optimizing our inventory levels, and improving our portfolio profitability.
On January 16, 2024, we completed the acquisition of American Pacific Corporation. AMPAC is the leading North American manufacturer of critical performance additives used in solid rocket motors for space launch and military defense applications. We report the financial results of our AMPAC business in our specialty materials segment.
Specialty materials sales were $27 million for the fourth quarter of 2024 and $141 million for the full year, surpassing our pre-acquisition expectations. Specialty materials operating profit was $1.5 million for the fourth quarter of 2024 and $17.5 million for the full year. The specialty materials full-year results include the sale of AMPAC finished goods inventory that we acquired at closing, and it was recorded at fair value and sold during the year at no margin.
We generated solid cash flows throughout the year and made payments of $373 million on our revolving credit facility since the AMPAC acquisition. We've turned $128 million to our shareholders through dividends of $96 million and share repurchases of $32 million. As of December 31, 2024, our net debt to EBITDA ratio was 1.2 which was a significant improvement over the 1.9 times we reported at the end of Q1.
As we look ahead to 2025 and beyond, we anticipate continued strength in our petroleum additives and specialty materials segments. We are committed to making decisions that promote long-term value for our shareholders and customers while staying focused on our long-term objectives. We believe that the core principles guiding our business, a long-term perspective, a safety-first culture, customer-focused solutions, technology-driven products, and a world-class supply chain will continue to benefit all our stakeholders.
Matthew, that concludes our planned comments. We are available for questions via email or by phone, so please feel free to contact me directly. Thank you all again, and we will talk to you next quarter.

Operator

Thank you. Everyone, this concludes today's event. You may disconnect at this time and have a wonderful day. Thank you for your participation.