MKSI - NASDAQ

Good day, and thank you for standing by. Welcome to the MKS Fourth Quarter and Full Year 2025 Earnings Conference Call. [Operator Instructions]. I would now like to hand the conference over to your speaker today, Paretosh Misra. Please go ahead, sir.

Good morning, everyone. I'm Paretosh Misra, Vice President of Investor Relations, and I'm joined this morning by John Lee, President and Chief Executive Officer; and Ram Mayampurath, Executive Vice President and Chief Financial Officer. Yesterday, after market close, we released our financial results for the fourth quarter and full year 2025, which are posted to our investor website at investor.mks.com. As a reminder, various remarks about future expectations, plans and prospects for MKS comprise forward-looking statements. Actual results may differ materially as a result of various important factors, including those discussed in yesterday's press release and in our most recent annual report on Form 10-K and any subsequent quarterly report on Form 10-Q. These statements represent the company's expectations only as of today and should not be relied upon as representing the company's estimates or views as of any date subsequent to today, and the company disclaims any obligation to update these statements. During the call, we will be discussing various non-GAAP financial measures. Unless otherwise noted, all income statement-related financial measures will be non-GAAP other than revenue and gross margin. Please refer to our press release and the presentation materials posted to the Investor Relations section of our website for information regarding our non-GAAP financial results and a reconciliation to of our GAAP measures. Our investor website also provides a detailed breakout of revenues by end market and division. Now I'll turn the call over to John.

Thanks, Paretosh, and good morning, everyone. 2025 was a year of impressive execution for MKS in a gradually improving demand environment. Year-over-year, we delivered 10% sales growth, 20% EPS growth and over 20% free cash flow growth. We maintained strong gross margins despite trade policy dynamics while staying focused on delivering for our customers, investing in our business and proactively bringing down our leverage. We're proud of our accomplishments in 2025 and grateful for the continued support and collaboration of our customers, suppliers and employees. Our partnerships and engagement have been critical as we work together to deliver the broadest portfolio differentiated solutions that are foundational to advanced electronics in the AI era. As we begin 2026, the demand outlook across our semiconductor and electronics and packaging markets is strengthening and we are already seeing this in the ambitious CapEx plans announced by large chip manufacturers. MKS has a long track record of outperforming WFE in rising spending environments and we are in an excellent position with our broad and deep portfolio of designed in products and are foundational to semiconductor manufacturing and electronics and packaging. I'll highlight some examples as I review our financial and end market performance. Our Q4 revenue, gross margin and earnings per diluted share all came in above the midpoint of the guidance ranges we provided on our Q3 call in November. Revenue was strong across all three of our end markets. In our semiconductor market, revenue was above the high end of our guidance, driven primarily by subsystems serving etch and deposition applications in the DRAM and logic foundry markets. Our plasma and reactive gases business delivered another strong quarter. We also maintained healthy momentum in dissolved gases for advanced logic applications and in back-end applications related to high bandwidth memory. Order activity in both areas remains robust. NAND-related activity remained stable sequentially as expected. I'm also pleased to note that our semiconductor business outperformed estimated WFE growth for the full year 2025, consistent with our track record of outperforming industry spending and improving demand environments. Looking to the first quarter, we expect semiconductor revenue to be up on a sequential basis. We believe this outlook is consistent with market views a steady improvement in industry spending over the course of the year. With our global footprint, broad product portfolio and deep technical expertise, we are ready to respond to demand as it comes with solutions that solve our customers' hardest problems and enable their increasingly complex road maps. On that front, we're excited to be ramping our new supercenter factory in Malaysia in the second half of this year, which will give us added capacity and resiliency to meet our customers' needs. Turning to Electronics & Packaging. Revenue came in near the high end of our guidance. The sequential increase was primarily driven by increased flexible PCB drilling and chemistry equipment sales. The Flex market continues to largely follow seasonal patterns tied to smartphone and PC cycles. And we also saw continued momentum in orders for our chemistry and chemistry equipment solutions for advanced PCBs related to AI applications. AI is driving increasing packaging complexity, and we are uniquely positioned to help our customers with the broadest portfolio of differentiated solutions. Excluding the impact of FX and palladium pass-through, the chemistry sales increased 16% in the fourth quarter and 11% for the full year compared to the same periods in 2024, reflecting another year of healthy growth. When we acquired Atotech in 2022, we saw the importance of advanced packaging for electronic devices, well ahead of many in our industry. With AI now rapidly driving demand for more complex PCBs with rapidly increasing numbers of layers, we are seeing growth despite multiyear softness in smartphones and PCs. Looking ahead to Q1 and the anticipated seasonal impact from the Luna New Year holiday, we expect electronics and packaging revenue to be up slightly sequentially and to increase in the low 20% range year-over-year. Key drivers for our expected performance in Q1 include higher flexible PCB drilling revenue and a continued strong performance in our chemistry equipment business. In our specialty industrial market, revenues came in at the high end of our guidance. We saw sequential improvement in research and defense in certain industrial applications. Looking ahead to Q1, we expect specialty industrial revenue to decline low to mid-single digits, mainly due to the Luna New Year holiday, which impacts our general metal finishing business. Year-over-year, we expect revenue to be up in the mid-single digits, led by the industrial and research and defense markets. Overall, our specialty industrial market continues to deliver steady performance and contribute attractive cash flows. Our fourth quarter performance and outlook for Q1 underscore our strong position across our 2 key end markets. In semi, we continue to strengthen our position in supporting leading-edge foundry and high-bandwidth memory investment through our vacuum and Photonics offerings while also remaining well positioned to capitalize on large scale investment in NAND equipment upgrades expected over the next several years. In Electronics and Packaging, we are demonstrating momentum with equipment and chemistries ideally suited to support a smaller, more complex and more vertical packaging structures for AI and other emerging devices such as foldable phones. We expect this business to grow over time as we realize long-term revenue streams from proprietary chemistries moving through production lines built with our equipment. The secular drivers powering our end markets are fully intact present exciting opportunities for MKS in the years to come. Our business is in a strong position with a resilient global footprint and margins that reflect the value we deliver and strong free cash flows that we are reinvesting into the business and using to pay down debt. Lastly, we are proud to have been honored for the third consecutive year as one of America's most responsible companies by Newsweek and Statista. In honor to reflects our continued focus and commitment to our people, customers and suppliers. Now let me turn it over to Ram to run through the financial results and first quarter guidance in more detail. Ram?

Thank you, John, and good morning, everyone. We ended the year with a very strong fourth quarter. Demand increased across all 3 end markets. We delivered healthy margins, robust free cash flow and made meaningful progress on our deleveraging goals. That progress has continued into the new year with another $100 million voluntary prepayment on our term loan in February as well as further optimization of our capital structure with the recently completed issuance of EUR 1 billion senior unsecured notes as a refinancing and extension of our term loan maturities. I'll cover these topics in detail in my remarks. Let me start with the results for the fourth quarter. MKS reported revenue of $1.03 billion, up 5% sequentially and 10% year-over-year. Fourth quarter semiconductor revenue was $435 million, up 5% sequentially and 9% year-over-year. The result was driven by strengthening demand, especially in DRAM and logic and foundry applications. The sequential increase was led by plasma and reactive gases products. Year-over-year comparisons reflect more broad-based strength across many product categories. providing further evidence of an improving semi demand environment. Fourth quarter Electronics & Packaging revenue was $303 million, an increase of 5% quarter-over-quarter and 19% year-over-year. This sequential improvement reflected higher flexible PCB drilling and chemistry equipment sales. The strong year-over-year comparison reflected healthy underlying growth across chemistry flexible drilling equipment and chemistry equipment. Chemistry sales in the quarter were up 16% year-over-year, excluding the impact of FX and palladium pass-through. Marking another strong year in chemistry revenue. In our specialty industrial market, fourth quarter revenue was $295 million, an increase of 4% sequentially largely due to the improvement in our research and defense markets as well as certain industrial applications. This was partially offset by a decline in automotive. Revenue was up 5% on a year-over-year basis, supported by modest improvement across several of our key market categories. However, automotive segment remain soft. Turning to gross margin. We reported fourth quarter gross margin of 46.4%, which is above the midpoint of our guidance. While margins were down year-over-year, it was a very solid performance given ongoing impact from higher tariffs, higher palladium prices, which are passed through at 0 margins and the effect of higher chemistry equipment in our overall mix. Fourth quarter operating expenses were $263 million, slightly above the guidance range, primarily due to higher variable compensation due to stronger-than-expected results. Fourth quarter operating income was approximately $217 million, yielding an operating margin of 21%, which is above our guidance midpoint. Fourth quarter adjusted EBITDA was $249 million, yielding 24.1% margin and also above the midpoint of our guidance. Net interest expenses was $42 million. Fourth quarter effective tax rate was 1%, which was in line with our guidance. We finished the year strong with fourth quarter net earnings of $168 million or $2.47 per diluted share which is above the midpoint of our guidance. We closed the quarter with approximately $1.4 billion of liquidity comprised of cash and cash equivalents of $675 million and our undrawn revolving credit facility of $675 million. Net debt at year-end was $3.6 billion, That, combined with improving adjusted EBITDA resulted in a net leverage ratio of 3.7x based on full year 2025 adjusted EBITDA of $966 million. Quickly summarizing our full year 2025 results. Revenue was $3.9 billion, up 10% year-over-year. Semiconductor revenue totaled $1.7 billion, up a healthy 13% year-over-year, driven by plasma and reactive gases and racking products. Our service business remained a steady and meaningful growth contributor. Electronics & Packaging revenue was $1.1 billion in 2025, up a strong 20% year-over-year. Total chemistry sales increased 11% year-over-year excluding the impact of foreign exchange and palladium pass-through. Specialty Industrial revenue was $1.1 billion, down 4% year-over-year primarily driven by softness in industrial markets, including automotive. Gross margin was 46.7%, down 90 basis points year-over-year, driven by additional costs related to tariffs and product mix, including record chemistry equipment sales. We moved quickly during the year to mitigate the impact of tariffs. That impact was largely mitigated on a dollar-for-dollar basis by the fourth quarter but will still continue to impact gross margin by about 50 basis points. Full year operating margin was 20.7%, down 60 basis points year-over-year as a result of lower gross margin. However, our operating expenses as a percentage of sales was 26% and improved by 30 basis points year-over-year. Let me now turn to cash flow and balance sheet discussion. For 2025, we generated operating cash flow of $645 million, an improvement of $17 million year-over-year. Even with an uptick in capital expenses, full year free cash flow was $497 million, an increase of 21% year-over-year and reflective of a very healthy conversion rate of our non-GAAP net earnings. In 2025, we made a total of $400 million of ordinary prepayments on our term loan. This month, we made another voluntary prepayment of $100 million. Since February 2024, we have paid down over $1 billion of our debt. We continue to remain focused on deleveraging. We also closed a few key financing transactions in recent weeks. The repricing of our term loan facility reduced credit spreads on our U.S. term loan by 25 basis points and the euro loan by 50 basis points. In connection with this repricing, we increased the size of our revolver to $1 billion. Finally, our successful EUR 1 billion bond offering has allowed us to diversify our capital structure, reduce interest rates on our debt, replace a portion of our secured debt with unsecured debt and extend our maturities. Based on current interest rates, the combined effect of these actions we took in this month will reduce annual interest expenses on a run rate basis by approximately $27 million. In addition, to lowering interest rates. These transactions will provide greater flexibility for the company. Finally, during the quarter, we paid a dividend of $0.22 per share or $15 million. As we announced last week, the Board authorized a 14% increase in the next dividend, which is payable in early March. Let me now turn to first quarter outlook, we expect revenue of $1.04 billion, plus or minus $40 million. By end market, our first quarter outlook is as follows: Revenue from semiconductor market is expected to be $150 million, plus or minus $15 million. Revenue from electronics and packaging market is expected to be $305 million, plus or minus $15 million and revenue from our specialty industrial market is expected to be $285 million, plus or minus $10 million. Based on anticipated revenue levels and product mix, including sequentially lower chemistry sales due to the Lunar New Year, we estimate first quarter gross margin of 4% to 6% plus or minus 100 basis points. We expect first quarter operating expenses of $270 million plus or minus $5 million. Looking to the rest of the year, we will continue to invest in the growth of our business, but we expect operating expenses to grow at a rate lower than revenue. We estimate first quarter adjusted EBITDA of $251 million plus or minus $24 million. We expect capital expenditures to average in the 4% to 5% of revenue through 2026. We expect a tax rate of approximately 21% in the first quarter. For the year, we expect our tax rate to be in the range of 18% to 20%. Based on these assumptions, we expect first quarter net earnings per diluted share of $2 plus or minus $0.28. Propping up, MKS continues to execute at a high level meeting growing customer demand and maintaining strong profitability. We continue to prioritize making the necessary investments in the business and proactive deleveraging. We believe that we are in an excellent position to capitalize on what we expect to be a robust demand environment. With that, operator, please open the call for questions.

[Operator Instructions]. Our first question comes from the line of Steve Barger with KeyBanc Capital Markets.

Thank you. I wanted to start with the 46% gross margin midpoint guide. How much of that is from chemistry equipment mix? And does the lower 1Q sequentially suggests an upward inflection in 2Q from higher chemistry sales volume? Or how do you expect that to play out as the year progresses?

Steve, this is Ram. I'll take that. I'll start with your second question. The answer is yes. It is due to the seasonality from lower chemistry driven by Lunar New Year and we expect the mix to improve in Q2 and further in Q3. So mix is the main reason for the 4% to 6% plus or minus 100 basis points guide.

Got it. And so that should be the low point of the year? Understood. And John, can we just talk about the memory shortage. It seems like that could be both good or bad for you. Can you talk about what you're seeing with NAND tool upgrades and other memory investments that could be coming. And then can you talk about what happens with consumer products just given the increase that you're seeing in the market?

Yes,Steve. So I think the customers and our customers' customers are putting a lot of the investments in DRAM, obviously, for AI, and that's causing this crunch in terms of availability of memory. I would say this, the industry is moving very fast to try to meet those demands. You see a lot of announcements of fabs going up and whatnot. And then more recently, NAND has become potentially a bottleneck as well in terms of availability. And so you saw one large chip company announced a new NAND factory, brand new greenfield us out a little ways, but that's good because it extends the ramps, as you will. In terms of upgrades, I think our customers are best to answer that. I would say this. We have plenty of capacity to meet those upgrades should they come. And as a reminder, our position in RF power for NAND vertical channel etching allows us to enjoy upgrades almost as much as greenfield. So I think NAND is something that's going to be kind of icing on the cake as that happens throughout the year and the next couple of years.

Got it. And then just any comment on consumer products, what the potential effect could be?

Yes. I mean I think it's going to depend on how much availability there is. I think you read some analyst reports, people are kind of thinking maybe low single-digit decreases in PCs and phones, but that really is going to be dynamic throughout the year. I think it's really going to be a function of how fast the industry can make those chips for that segment of the market. So I think if we have a little decrease in PCs and smartphones, I think it's going to be more than made up with AI.

Our next question will come from the line of Jim RicchiutI with Needham & Company.

Thank you. Yes, I'm wondering if we look at the electronics and packaging business, the 20% plus growth in 2025, John, any sense as to how much of that was a function of capacity additions. And I'm curious how much of a tailwind would you anticipate this being in 2026 in this area of the business?

Yes, good question, Jim. I think what we said also is that while the electronics and packaging grew 20%, chemistry grew about 11% year-over-year. So that's great growth, too. So chemistry would be more utilization dependent. And then the rest of that growth is capacity additions from chemistry equipment as well as flex drilling equipment. So we've talked about our chemistry equipment. That's a nice leading indicator of future chemistry revenue. We're now into the fifth quarter of strong bookings and revenue for that. I think in the past, we talked about the first half of '26. Our factories are full through then. I think we're not going to guide bookings going forward in equipment, but I would say the difference between 90 days ago is we continue to see strong chemistry. So I think that continues, and that's really just something that, over time, will lead to that high gross margin chemistry revenue that will be on our production equipment.

And a follow-up just on -- you highlighted the improving demand in CD drilling equipment. How would you characterize the recovery that you're seeing in this part of the business. versus previous cycles. I know it's been a while since we've seen a decent upturn in this business.

Yes, I know you've covered ESI for a long time, Jim. I would say there was a super cycle maybe 4 or 5 years ago. This is more like a normal cycle. So probably 2 years now where it's kind of been more normalized. So we're happy to see that. I have to see that our share continues to be very strong. and that some new devices that we talked about full phones are driving more flex demand. So I think I would characterize this as not a super cycle, if you will, for Flex, but more of a normalized cycle that we have expected on a more consistent basis throughout the years.

One moment for our next question. Our next question will come from the line of Melissa Weathers with Deutsche Bank.

Thank you for the question. John, I was hoping to ask you to pull out your crystal ball and get your opinion on WFE growth this year. So we've heard some pretty strong outlook from some of your customers and peers on WFE. Any sense of magnitude or how are you guys thinking about like the magnitude of growth the equipment spending could have this year? And then how should we think about that flowing through to your semiconductor system sales?

Yes. I'll pull out my crystal ball, Melissa, it's cloudy, but I guess it's a positive. A couple of our edge customers are talking about 20% year-over-year WFE growth, a couple of our listometrology customers are talking more in the mid-teens, if you will. So you put it all together, WFE will be a large grower. And I think more importantly, I think everybody is kind of assuming it's more than just a 1-year thing. It's going to be a cycle that maybe lasts longer than that. MKS has always outperformed during the upturn. That's just math. Everything is designed in already in an upturn. People are just ordering things that are already designed in. We have to ship before our customers could ship. At the same time, during a ramp our customers are going to try to build inventory. And so all that leads to outperformance. Even in 2025, when there wasn't really a ramp I believe we will have shown that we outperformed WFE even in a relatively stable 2025. And I would say in my commentary a couple of months ago, the ramp has started. We have started. Supply chain teams are working hard with our suppliers. We're in constant communication with our customers and everybody in the industry is getting ready for this ramp. And MKS, as you know, is supporting 85% of WFE. So we're going to see all of that. And we're really looking forward to meeting that demand. I think we also talked about the Malaysia plant. Which will come online midyear. And that will give us just extra flexibility in the future. But our factories today are ready to meet the demand that we see in the next year or 2.

Perfect. And then maybe following up on something you've already touched on, on the call, but the ability for the AI side of things sort of offset the -- any slowness that we could see in consumer electronics. And you talked about like the board complexity and layer counts going up for AI boards. Is there any other way to quantify like what is your revenue opportunity with or 2027 Board versus what you've seen in the past? Just any other way to frame how we should think about that content opportunity and sort of how much that could offset any weakness on the consumer electronics side.

Yes. Maybe the way to think about it is, let's say, smartphones. The number of layers and the PCBs for smartphones could be in that 10 to 12 layers, give or take, and it's increasing as well. but the HDI type of boards for AI are in that 15% to 20% already. And in addition, AI also needs multilayer boards, which are in the 30 to 40 layers. And then, of course, the substrate -- the package substrate layers. So I would say that PCs and smartphones, the number of layers is consistent. It goes up a couple of layers every cycle. The AI, we're talking about doubling the number of layers. And so we've talked about in the past that our chemistry revenue from AI in 2024 was about 5% of our revenue -- our chemistry revenue in Electronics & Packaging. And now in 2025, it's 10%. And I would say it's a sequential increase quarter-on-quarter-on-quarter in '25. So we expect AI to continue taking a larger percentage of our chemistry revenue even with a slightly muted PC and smartphone market.

And one moment for our next question. Our next question will come from the line of Michael Mani with Bank of America Securities.

To start, I just wanted to ask about your capacity position what this Malaysia facility fully ramping over the next course of next year? How much revenue do you think that could ultimately support for your business? And if there's any way to kind of quantify how much that footprint has expanded for you over the last couple of years to be great. And then as you look out, are there any other areas where you feel like you need to invest in your capacity position? I know there's a Thailand facility that you're ramping up, I believe that's for chemistry, but anywhere else where you anticipate any supply constraints?

Yes. Thanks, Mike, for the question. I think with Malaysia, it was built as a business economy replan. It wasn't built to anticipate needed more capacity for this particular ramp. So we already have plenty of factory capacity for that. I think Malaysia is kind of think about it as future capacity needs for WFE. We haven't sized it. I would say this, we always build our factories and phases. So we have the shell and then we'll put in a certain amount of lines and product lines beginning middle of this year. And then we'll plan on what makes sense to grow there. But it will give us a lot more capacity than we have currently. I would say we've added a little bit of CapEx here and there, kind of nip and up with our factories in anticipation of this particular cycle. But we had talked about being ready for $125 billion WFE 3 years ago. and we did that. And remember that $125 billion is run rate. We always have 30% surge capacity in addition to that. So I think we're quite comfortable with our capability I think always in ramp constraints or supply chain. Our suppliers are better, they're bigger, they're ready, but the golden school effect will happen. And so that's really where our execution has always been among the best, is finding those issues and then dealing with them and delivering to our customers on time. And we've always done that through every cycle. So I'm very confident we'll have the capacity. We have the team and the supply base to help us deliver to our customers this ramp as well.

Very helpful. And just moving on to electronics and packaging. So as you look out over this next year, is it fair to say that most of the growth this year, if it is sustainable in this kind of double-digit growth area would be -- would largely come from more chemistry revenue now that you've seen significant equipment orders over the last couple of months that are going to be ramping in terms of utilization? And then more broadly, this kind of relates to the previous question. I think in the past, you've said that every $100 million in install equipment translates to $20 million to $40 million in chemistry sales per year for utilization. So I just wanted to ask what are the sensitivities around that? Is the revenue function much higher if it's a substrate versus will be and as your customers are talking about pushing a number of layers to over 100. Like what does that do to that attach rate for revenue?

Yes. Thanks, Michael. I think in general, our model is still the same, $20 million to $40 million is per $100 million of equipment sales. And it doesn't really change too much between particular types of boards. And it's really a function of utilization. So if that tool is running 100%, then you're getting into that $20 million to $40 million range. And then I think, in general, we're just very happy with the continued shipments of our equipment, as I said in the earlier question, it continues to get better. It continues to be consistently strong even from a quarter ago. So if that's the case, then we will have had potentially 2 good years of record level chemistry equipment shipments. Now I also think we've talked about how long does it take for a piece of equipment to turn into chemistry revenue. We've said 18 to 24 months. That's still the case. So a lot of the chemistry revenue that you saw grow in 2025 was with equipment we shipped in 2021, 2022. And so that's why I think the equipment we're shipping now will be great capacity for future chemistry going forward into -- into '26, '27 and going forward. So I just want to make sure that was clear. The chemistry revenue now is not constrained by the equipment more shipping. That chemistry revenue is growing because of the capacity we've already shipped in terms of equipment a few years ago.

Our next question comes from the line of Shane Brett with Morgan Stanley.

I want to follow up on Mani's question. Just based on the knowledge you currently have, should we be anticipating chemistry revenue to accelerate or decelerate in 2026? And I'm asking this because I want to better figure out just how much of this chemistry revenue is associated with just higher growth AI or should be kind of benefiting from a higher installed base. But how much could be impacted by just weaker consumer electronics sales.

Yes, Shane, I think, well, there is a seasonality to the chemistry revenue, as Ron pointed out. So Q1 is for the consumer product cycle type of products is lowest. Because of Lunar New Year. And then the Consumer Products chemistry will continue to grow throughout the year. That's the consumer product cycle. To your point, if there's a single-digit decrease, then we'll see that in that chemistry revenue for that market. But at the same time, AI chemistry is really -- we are expecting that to continue to grow. All our customers that are in that AI supply chain are running capacity, they continue to add tools and add -- and bring those tools up. So I think, as I said, that's why I expect that even with a slight decrease in PCs and smartphones the AI part of the chemistry will more than make up for that.

Got it. And for my follow-up, on the E&P tooling side, late last year, you sort of mentioned that your book through the first half of 2026. Just how should I think about this E&P to -- your current capacity for E&P tools relative to the existing demand for these tools.

Yes. I think we've added some capacity. We didn't need to build a new factory if you -- if that's your question. And we've been able to meet the timing demands of our customers even at these elevated levels. And as I said earlier in the commentary, based on changes from 90 days ago, we continue to see these strong bookings. So I think it's going to be another strong year for equipment. And our capacity to meet the time lines need by our customers right now is sufficient. We're not constraining our customers.

Our next question comes from the line of David Liu with Mizuho.

Let me ask the question. On for Vijay at Mizuho. Maybe the first one just back on WFE. I think your customers and peers have mentioned second half-weighted strength and acceleration. Do you think like we can see that and revenue hit probably a 5 handle starting in September, December?

Sorry, David, 5 handle...?

On semis revenue.

Semis revenue, I see. It's -- we're guiding 450 years. Well, I would say this, if WFE grows in that same range between 15% to 20% as many of our customers are saying, we're going to have to ship ahead of that. We're going to have to shift to build that revenue for their inventory. I think in the past, we have hit that 5 handle at the last ramp. That wasn't constraints from our factories, that's constrained some supply chain, right? And so I think that -- I think we're better at managing supply chain. I think the supply chain is better. So 5 handle would not be surprising. I just can't predict when it will be. But in order to meet a 20% WFE increase. We have to get to a 5 handle probably as MKS. Otherwise, the industry won't get to that 20%.

Got it. And then a longer-term question, I think part of the industry is beginning to look at moving to panel for advanced packaging. I'm just wondering what kind of conversations you guys are starting to have there in the advanced packaging side and if there's any sort of outlook or time line that benefits and KSI.

Yes. I think you're referring to redistribution layers going from wafer shaped to panel rectangular shape. And I think -- many customers are working on that. And of course, when they go to panel, that's MKS. We are participating in the wafer type of packaging. But our strength has always been in panels. And so that is a tailwind for MKS. But as I mentioned in the past, that's kind of 1 or 2 layers of redistribution layers, and that is still relatively small in terms of market growth for us because the HDI and MOB are growing at 10 layers a year or more each. So while it's a tailwind, I think we don't want to miss the bigger picture, which is that the number of layers of MLB and HDI and package substrates are growing much faster.

[Operator Instructions]. Our next question will come from the line of Peter Peng with JPMorgan.

Some of your semi customers are already talking about inventory build. Have you seen that in your -- in the second half of 2025? Or are you starting to see that now in terms of inventory build?

Yes. Well, you can look at their inventory numbers and you see if it's building. But I would say this, Peter, a lot of the conversations on getting ready happened in that Q4 time frame, and they have continued to accelerate in the Q1 time frame. And so we're ramping our factories in our supply chain. And I think it will take a little while to show up as inventory build in our customers because right now, we're -- as a supply chain, we're all just getting ready to just meet the higher demand. So you'll probably see that build up in their inventory numbers over the next couple of quarters. But we are still shipping to demand at this point just because we're just in the early stages of that ramp.

Got it. And then in the lines, there's a lot of, I guess, constraints and greenfield capacities even from your end customers as you kind of engaged, is there any -- I guess, are you seeing any constraints from your customers where they just don't have enough space to move equipment yet. And so maybe you can talk about that dynamic.

I've not heard that, Peter. I think our customers are well run customers. They have large factories located globally. At the last ramp we all added capacity, got more efficient. So I don't see that as a constraint in terms of not enough space to build the tools, if that was your question.

And one moment for our next question. Our next question comes from the line of Joe Quatrochi with Wells Fargo.

Maybe just kind of on that line of thinking on the semi business. You're guiding for kind of 3-ish percent sequential growth, and I think some of your main customers are guiding for high single-digit, low double-digit sequential growth through the first quarter. So just kind of curious if you could kind of give us the puts and takes there.

Yes, Joe, I think we're guiding based on what we -- our best view today. But I think you've been in this industry a long time. When that ramp occurs, it just accelerates fast. This is our best view today. But during a ramp, as you know, things can accelerate rapidly. And so we're going to stick to this guidance. But certainly, we give a range. And even last quarter, we gave a range and we went higher than the upper end of that range. And that's kind of a characteristic of ramps. And so this is what we see today. I would say this, if we could ship more, our customers will probably take it. So we're trying to ramp as fast as we can.

That's helpful. And then maybe just as we think about the ramp of the course of the year and think about just the puts and takes on gross margin, should we still think about 50% is kind of incremental gross margin leverage just thinking about the tariff dynamic as well?

Joe, this is Ram. I'll take that. The quick answer is yes. We are very pleased with the gross margin for 2025. And if it weren't for tariffs, you would have been to your point or 47%. And if you remember, last 3 quarters, we were focused on mitigating the cost of the tariffs. And by we offset the cost dollar for dollar. And going forward, we'll be focused more on mitigating the impact on the gross margin itself. So yes, the volume and the right mix will certainly get us back to the 4%.

[Operator Instructions]. Our next question will come from the line of James Schneider with Goldman Sachs.

Just as a clarification initially, you talked about your semi customers citing a 15% to 20% outlook and your ability to kind of do towards the high end of that, presumably, given the mix of your customers and the mix of your business You'd also just referenced potential constraints in terms of ramping your production. Can you maybe just give us a clarity on whether you see yourselves as constrained in your ability to ship in the next quarters? Do you think you'll be able to catch up to your customers' full demand -- unconstrained demand run rate by the middle of the year at least?

Yes, I'd say this is Jim. During the beginning of the ramp, we're never the constraint because I think we have a supply chain with inventory as well. And even during the peak ramp and even after many quarters of a ramp, we have never constrained our major customers. And I think it's an industry that's always met demand as an entire semiconductor industry. And companies that don't meet demand and constrain their customers they're not around anymore, right? And so I think we have plant capacity. The challenge is getting the supply chain to ramp up. But even then our biggest customers have always been a priority and we've never disappointed them.

Very clear. And then just in terms of how we think about the forward model, you've clearly stated that you expect to grow OpEx slower than revenue, but give us a sense about the leverage you expect there, please? 2:1 or et cetera?

Jim. So if you look at -- so we will be investing. We want our OpEx very carefully, but we will be investing this year to support the growth. But in terms of leverage. That will be a focus to drive our leverage further. If you look at 24% to 25%, our OpEx dollars grew, but our OpEx as a percentage of sales was lower. So we finished around 26% for 25 and 26, we will be lower than that.

Thank you. And I would now like to hand the conference back over to Paretosh Misra for closing remarks.

Thank you all for joining us today and for your interest in MKS. Operator, you may close the call, please.