UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) x QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2025 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from _________ to __________ Commission file number: 001-35931 Constellium SE (Exact name of registrant as specified in its charter) France 98-0667516 (State or ot ...

Financial Data and Key Metrics Changes - Shipments were 372,000 tons, down 2% compared to Q1 2024 due to higher pulp shipments offset by lower A&T and AS&I shipments [6] - Revenue increased to $2 billion, a 5% rise compared to Q1 2024, primarily driven by higher metal prices [6] - Net income for the quarter was $38 million, up from $22 million in the same quarter last year [6] - Adjusted EBITDA was $186 million, including a positive noncash impact from metal price lag of $46 million; excluding this, adjusted EBITDA was $140 million, down from $160 million last year [7] - Free cash flow was negative $3 million, in line with expectations, but the company expects to generate positive free cash flow exceeding $120 million for the year [8][26] Business Line Data and Key Metrics Changes - A&T segment adjusted EBITDA decreased 14% to $75 million, with aerospace shipments down 11% and TID shipments down 7% [17][18] - Park segment adjusted EBITDA increased 25% to $60 million, with packaging shipments up 9% while automotive shipments decreased 15% [19][20] - AS&I segment adjusted EBITDA decreased 50% to $16 million, with automotive shipments down 14% and industry shipments down 4% [21][22] Market Data and Key Metrics Changes - Demand weakness was noted across most end markets outside of packaging, particularly in automotive [9] - Aerospace market backlogs remain robust, but supply chain challenges continue to impact deliveries [30] - Packaging demand remains healthy in North America and Europe, with expectations for low to mid single-digit growth [32] - Automotive production remains below pre-COVID levels, with expectations of continued weakness due to tariffs [33] Company Strategy and Development Direction - The company is focused on strong cost control, free cash flow generation, and capital discipline [9][36] - Accelerated cost reduction efforts under the Vision 25 program are in place to optimize capacity based on market conditions [16][24] - The company is working on mitigating tariff impacts through customer pass-throughs and exploring alternative sourcing [10][61] Management's Comments on Operating Environment and Future Outlook - Management expressed confidence in long-term fundamentals driving aerospace demand despite near-term challenges [30] - The company remains cautious about the automotive market outlook due to tariff impacts and reduced production forecasts [54] - Management believes that current market conditions will eventually improve, and the company is well-positioned for long-term success [36][89] Other Important Information - The company returned $15 million to shareholders through share repurchases during the quarter [8][36] - Net debt at the end of Q1 was $1.8 billion, with leverage at 3.3 times, expected to trend down by year-end [28][29] Q&A Session Summary Question: What drove the better-than-expected performance in Q1? - Management attributed the performance to improvements at the Muscle Shoals plant and progress on the Vision 25 cost reduction program [41][42] Question: Is the inventory issue in aerospace resolved? - Management indicated that while their inventories are controlled, the supply chain is still struggling to ramp up [45] Question: What is the outlook for aerospace and automotive markets? - Aerospace is expected to remain choppy, while automotive demand is softening, particularly due to tariffs [52][54] Question: What is the expected cost impact from tariffs? - The gross impact from tariffs is estimated at $20 million for the rest of the year, with efforts to mitigate this through customer pass-throughs [55] Question: How is the company managing scrap costs? - Management noted that scrap costs are becoming more favorable, and they are working to optimize their sourcing strategies [66][69] Question: What is the outlook for the packaging segment? - The packaging segment is expected to benefit from improved demand and operational performance, particularly at the Muscle Shoals facility [72][74]

Financial Data and Key Metrics Changes - Shipments decreased by 2% to 372,000 tons compared to Q1 2024, primarily due to lower shipments in A and T and AS and I segments [6] - Revenue increased by 5% to $2 billion compared to Q1 2024, driven by higher metal prices [6] - Net income rose to $38 million from $22 million in the same quarter last year [6] - Adjusted EBITDA was $186 million, including a positive noncash impact from metal price lag of $46 million; excluding this, adjusted EBITDA was $140 million, down from $160 million last year [7] - Free cash flow was negative $3 million, with expectations to generate over $120 million in positive free cash flow for the year [9][28] - Leverage at the end of Q1 was 3.3 times, expected to trend down by year-end [9][30] Business Line Data and Key Metrics Changes - A and T segment adjusted EBITDA decreased by 14% to $75 million, with aerospace shipments down 11% and TID shipments down 7% [18][19] - Park segment adjusted EBITDA increased by 25% to $60 million, with packaging shipments up 9% but automotive shipments down 15% [20] - AS and I segment adjusted EBITDA decreased by 50% to $16 million, with automotive shipments down 14% and industry shipments down 4% [22] Market Data and Key Metrics Changes - Demand in aerospace remains stable, with healthy demand for military aircraft, but supply chain challenges persist [32] - Packaging demand is healthy in North America and Europe, with long-term growth expected [34] - Automotive production remains below pre-COVID levels, with demand softening in North America and Europe, particularly in luxury and electric segments [35] Company Strategy and Development Direction - The company is focused on strong cost control, free cash flow generation, and capital discipline amid challenging market conditions [10][39] - Accelerated cost reduction efforts under the Vision 25 program to optimize capacity and reduce costs [16][25] - The company is adapting to market conditions by shifting capacity from automotive to packaging markets [16] Management's Comments on Operating Environment and Future Outlook - Management acknowledges ongoing demand weakness across most end markets but remains optimistic about long-term fundamentals [32][39] - The tariff situation is seen as both a challenge and an opportunity, with efforts to mitigate impacts through customer pass-throughs [11][16] - The company expects to maintain guidance for 2025, targeting adjusted EBITDA of $600 million to $630 million and free cash flow exceeding $120 million [39] Other Important Information - The company returned $15 million to shareholders through share repurchases during the quarter [9][39] - The impact of tariffs is estimated at $20 million for the remainder of the year, with ongoing efforts to mitigate these costs [13][57] Q&A Session Summary Question: What drove the better-than-expected performance in Q1? - Management attributed the performance to improvements at the Muscle Shoals plant and progress on the Vision 25 cost reduction program [42][43] Question: Is the inventory issue in aerospace resolved? - Management indicated that while their inventories are controlled, the supply chain still faces challenges [47] Question: What is the outlook for aerospace and automotive markets? - Aerospace is expected to remain choppy, while automotive demand is uncertain due to tariffs and market conditions [53][55] Question: How will tariffs impact costs? - The gross impact of tariffs is estimated at $20 million, with efforts to pass through costs to customers [57] Question: What is the outlook for scrap metal costs? - Management noted that scrap spreads are improving, which is beneficial, but costs remain a headwind relative to historical levels [71] Question: How is the company positioned for future demand in defense applications? - There are positive signs for increased demand in defense, with management ramping up inventories in response [87]

Group 1 - Constellium (CSTM) reported quarterly earnings of $0.26 per share, significantly exceeding the Zacks Consensus Estimate of $0.07 per share, and up from $0.12 per share a year ago, representing an earnings surprise of 271.43% [1] - The company posted revenues of $1.98 billion for the quarter ended March 2025, surpassing the Zacks Consensus Estimate by 1.42%, and an increase from $1.88 billion year-over-year [2] - Constellium has surpassed consensus EPS estimates two times over the last four quarters and has topped consensus revenue estimates twice as well [2] Group 2 - The stock has underperformed the market, losing about 6.6% since the beginning of the year compared to the S&P 500's decline of 5.5% [3] - The current consensus EPS estimate for the coming quarter is $0.28 on revenues of $2.15 billion, and for the current fiscal year, it is $1 on revenues of $8.16 billion [7] - The Zacks Industry Rank indicates that the Metal Products - Distribution sector is currently in the bottom 25% of over 250 Zacks industries, which may impact stock performance [8]

Exhibit 99.1 April 30, 2025 Constellium Reports First Quarter 2025 Results and Maintains Full Year 2025 Guidance Paris - Constellium SE (NYSE: CSTM) ("Constellium" or the "Company") today reported results for the first quarter ended March 31, 2025. Jason Hershiser Delphine Dahan-Kocher Phone: +1 443 988-0600 Phone: +1 443 420 7860 1 • Shipments of 372 thousand metric tons, down 2% compared to Q1 2024 • Revenue of $2.0 billion, up 5% compared to Q1 2024 • Net income of $38 million compared to net income of $ ...

Q1 2025 Performance - Shipments reached 372 thousand tons, a decrease of 2% year-over-year[11] - Revenue totaled $2.0 billion, an increase of 5% year-over-year[11] - Net income was $38 million[11] - Adjusted EBITDA was $186 million, including a positive $46 million non-cash metal price lag impact and a negative $10 million impact from the Valais flood[11] - Free Cash Flow was $(3) million, which includes a negative $27 million impact at Valais due to the flood[11] - The company repurchased 1.4 million shares for $15 million[11] - Leverage ratio stood at 3.3x at the end of March 31, 2025[11] Segment Performance - Aerospace & Transportation segment Adjusted EBITDA was $75 million, a decrease of 14% year-over-year, with shipments of 51 thousand tons, down 11%[14] - Packaging & Automotive Rolled Products segment Adjusted EBITDA was $60 million, an increase of 25% year-over-year, with shipments of 269 thousand tons, up 2%[18] - Automotive Structures & Industry segment Adjusted EBITDA was $16 million, a decrease of 50% year-over-year, with shipments of 52 thousand tons, down 12%[21] 2025 Expectations - The company expects Free Cash Flow to be greater than $120 million[28] - Capital expenditures are projected to be approximately $330 million[28] - Cash interest expenses are estimated at around $120 million[28] - Cash taxes are expected to be approximately $40 million[28] Targets - 2025 Adjusted EBITDA is targeted between $600 million and $630 million[43] - 2028 Adjusted EBITDA is targeted at $900 million[43] - 2028 Free Cash Flow is targeted at $300 million[43]

Core Viewpoint - Constellium SE reported solid financial results for Q1 2025 despite ongoing demand weakness in most end markets, with a focus on cost reduction and operational performance [2][3][4] Financial Performance - Q1 2025 shipments totaled 372 thousand metric tons, a decrease of 2% compared to Q1 2024 [4][43] - Revenue for Q1 2025 was $1.979 billion, representing a 5% increase from $1.880 billion in Q1 2024 [3][6] - Net income increased to $38 million in Q1 2025 from $22 million in Q1 2024 [3][14] - Adjusted EBITDA rose to $186 million in Q1 2025, up from $146 million in Q1 2024 [3][6] Segment Performance - Aerospace & Transportation (A&T) segment reported Adjusted EBITDA of $75 million, down 14% from $87 million in Q1 2024, with shipments decreasing by 11% [7] - Packaging & Automotive Rolled Products (P&ARP) segment saw Adjusted EBITDA increase by 25% to $60 million, with shipments up 2% [8] - Automotive Structures & Industry (AS&I) segment's Adjusted EBITDA fell 50% to $16 million, with shipments down 12% [9] Cash Flow and Capital Management - Cash from operations was $58 million, while Free Cash Flow was negative at $(3) million [15][16] - The company repurchased 1.4 million shares for $15 million during the quarter [5][17] - Leverage ratio stood at 3.3x as of March 31, 2025 [5] Outlook - The company maintains its guidance for 2025, expecting Adjusted EBITDA between $600 million and $630 million, and Free Cash Flow exceeding $120 million [2][20] - Long-term targets include Adjusted EBITDA of $900 million and Free Cash Flow of $300 million by 2028 [20]

Company Announcement - Constellium SE will host a conference call and webcast on April 30, 2025, at 10:00 AM (Eastern Time) to announce its first quarter 2025 results [1] - The press release regarding the results will be sent before market opening [1] Conference Call Details - The conference call will be led by CEO Jean-Marc Germain and CFO Jack Guo [1] - Details for accessing the conference call and webcast are available on the Constellium Investor Relations page [2] - A telephone participation option is provided with specific numbers for the United States, France, Germany, Switzerland, and the United Kingdom [2] - An archived recording of the conference call will be available for three weeks on the company’s website [2] Company Overview - Constellium is a global leader in developing innovative, value-added aluminum products for various markets, including aerospace, packaging, and automotive [3] - The company generated $7.3 billion in revenue in 2024 [3]

Core Viewpoint - Constellium SE is preparing for its Annual General Meeting of Shareholders scheduled for May 15, 2025, and has made relevant documents available for shareholders [1][2] Group 1: Company Overview - Constellium is a global leader in developing innovative, value-added aluminum products for various markets, including aerospace, packaging, and automotive [2] - The company generated $7.3 billion in revenue in 2024 [2] Group 2: Shareholder Information - The Proxy Statement and other documents for the Annual General Meeting are accessible on the company's website and can be obtained free of charge by contacting the Corporate Secretary [1]

Core Insights - Constellium SE released its 2024 Sustainability Report, emphasizing its commitment to a sustainable and circular economy, with progress on decarbonization, recycling, safety, and women's representation [1][4] Sustainability Achievements - The company achieved significant milestones in sustainability, including the inauguration of a €130 million recycling center in France, increasing global recycling capacity to over 750,000 metric tons annually, enhancing recycling of automotive and packaging products by 75%, and reducing carbon emissions by 400,000 metric tons CO₂eq [6] - Constellium closed its last coal-fired power station in Germany, expected to reduce direct greenhouse gas emissions by over 25% from 2021 to 2025 [6] - The company completed its first industrial-scale hydrogen casting, substituting natural gas with hydrogen for aluminum production, showcasing the potential of green hydrogen in decarbonizing industrial processes [6] Recognition and Certifications - Constellium received a Gold rating from Ecovadis and an AA rating from MSCI for its sustainability efforts, and its operations were certified by the Aluminium Stewardship Initiative (ASI) under Performance Standard v3.0, highlighting leadership in responsible sourcing and greenhouse gas reduction [2][6] Employee Initiatives - The launch of the WINS (Women Inspiring Networking and Success) Employee Resource Group in 2024 aims to promote inclusion and empowerment among all employees [6]