Please note that this event is being recorded. I would now hand the call over to Scott Gaffner, Senior Vice President, Investor Relations, to begin.
Thank you, good morning, everyone. Before we get started, I want to remind you that certain statements made on this call contain forward-looking information. Forward-looking statements are not guarantees of performance and, by their nature, are subject to uncertainties. Actual results may differ materially. Please see our webcast slides and the company's SEC filings for additional risk factors and disclosures. Any forward-looking information speaks only as of this date, and the company undertakes no obligation to update the information to reflect change to circumstances. Additionally, today we'll use certain non-GAAP financial measures. Required information about these measures is available on our webcast slides and in our press release, both of which are posted on our website at wesco.com. On the call this morning, we have John Engel, Wesco's Chairman, President, and CEO, and Indraneel Dev, Executive Vice President and Chief Financial Officer.
Now I'll turn the call over to John.
Thank you, Scott. Good morning, everyone. Thank you for joining our call today. We delivered an exceptional start to 2026, building on last year's market outperformance and accelerating business momentum. In the first quarter, sales, backlog, operating margin, adjusted earnings per share, and free cash flow all increased versus the prior year and exceeded our expectations. Record first quarter sales of $6.1 billion were up 14%, marking our third quarter in a row of double-digit sales growth. Booming data center demand remains a significant growth driver of our business. Data center sales of $1.4 billion were up approximately 70% versus prior year and represented 24% of total company sales in the quarter.
Overall, our business momentum continued to accelerate in the quarter, with organic sales up sequentially, outpacing normal seasonality and reinforcing the strength and durability of demand across our end markets. This performance reflects broad-based strength across our entire portfolio, led by continued strong momentum in CSS and EES, along with improving trends in UBS. We again ended this quarter with a record backlog, up 22% versus prior year, reflecting the continued effectiveness of our cross-selling program and providing clear visibility of the secular growth trends on our business. Profit growth, margin improvement, and free cash flow generation were also excellent in the first quarter. Adjusted EBITDA grew 25%, and adjusted EBITDA margin expanded 60 basis points, driven by gross margin expansion and strong operating cost leverage on our double-digit sales growth. Adjusted diluted earnings per share was up 52% versus the prior year.
Free cash flow generation at 128% of adjusted net income was also very strong, underscoring our disciplined execution and continued focus on working capital management. We're very pleased with our first quarter results. While we remain mindful of the volatility of the broader macroeconomic environment, we see positive momentum continuing across our business. As a result, we are raising our full-year outlook for 2026. As the market leader and with positive momentum building, I'm confident that Wesco will continue to outperform our markets through disciplined execution, our differentiated value proposition, and the strength of our global platform. Our Wesco team remains focused on driving strong growth and margin expansion and delivering superior value to our customers and shareholders. One final comment. As we announced earlier this year, David S. Schulz is retiring from Wesco, and Indraneel Dev has joined our team as CFO.
I would like to thank Dave for his outstanding leadership, his dedicated service, and his tremendous contributions to Wesco and our overall success over the past 10 years. We wish Dave and his family our very best. Neil's off to a great start as Wesco's new CFO, and I will now turn it over to him to take you through our excellent first quarter results and raised full-year outlook in more detail. Neil.
Thank you, John, and good morning, everyone. I'd like to thank John and the board for the opportunity, and I want to recognize Dave for his leadership and thank him for his partnership during this transition. Before turning to our results, I'll take a minute to touch on my near-term priorities. I intend to focus on partnering with the leadership team to scale our business in attractive end markets, drive profitable growth, continued market outperformance, and deliver strong cash flow with disciplined capital allocation. That mindset has been shaped by working across both public and private companies, often in complex global, highly competitive technology and capital-intensive businesses. John and I are aligned on the initial focus areas where we have the potential for taking our existing great capabilities to the next level.
First, driving operating leverage and margin expansion as we scale, particularly in data centers and other high-growth end markets. This will be accomplished by a combination of partnering with our business leaders to ensure that our commercial and go-to-market strategy reflects our enhanced value proposition and partnering with our functional leaders on continuing to improve our cost structure. It's all about profitable growth. Second, improving working capital efficiency and cash conversion through tighter processes, analytics, and execution discipline. This is not just about back office, it's about optimizing our end-to-end capabilities from sales funnel to cash collection. Transitioning to our results, let me start with the highlights for the quarter. We delivered strong organic sales growth year-over-year, with sequential performance better than typical seasonality. Profitability improved with meaningful EBITDA margin expansion.
EPS was up more than 50%, and free cash flow generation was strong at 128% of net income. With that, let me turn to our first quarter results starting on Slide 4. We delivered an excellent first quarter, with reported sales of $6.1 billion, up 14% year-over-year, including 12% organic growth. We delivered volume growth across all three SBUs and realized an estimated price benefit of approximately 3 points. Gross margin was 21.2%, up approximately 20 basis points year-over-year, and SG&A operating leverage improved by 40 basis points. As a result, adjusted EBITDA increased 25% to $389 million, and adjusted EBITDA margin expanded 60 basis points to 6.4% of sales. Turning to Slide 5.
Adjusted EPS increased 52% year-over-year to $3.37. The year-over-year improvement was driven primarily by stronger operating performance in the quarter, reflecting higher sales and improved profitability. Additionally, EPS growth benefited from a lower tax rate and from the absence of the preferred stock dividend following last year's redemption. Turning to Slide 6. CSS delivered another excellent quarter, with organic sales up 22% year-over-year and reported sales up 24%. This growth was driven by continued strength in Wesco Data Center Solutions, which delivered a record quarter with sales up over 60%. Within the rest of the portfolio, security delivered high single-digit growth while enterprise network infrastructure declined mid-single digits due to weakness in the service provider market. However, including data center-related sales, enterprise network infrastructure grew high teens year-over-year.
Overall, organic growth was driven primarily by volume, up about 21%, with price contributing approximately 1%. Backlog ended the quarter at a record level and was up approximately 40% versus the prior year, reflecting continued strong data center project activity and order rates. Profitability also improved meaningfully, and our focus remains on margin expansion as we scale the business, particularly in our data center markets. Adjusted EBITDA increased 41% to $223 million, and adjusted EBITDA margin expanded 110 basis points to 9%. Importantly, despite some modest pressure on gross margin from large data center projects, we generally see healthy and accretive EBITDA margins for Wesco Data Center Solutions. Moving to Slide 7. EES delivered solid growth in the quarter, with organic sales up 7% and reported sales up 9% year- over- year.
Growth was driven by strong execution in OEM and construction. OEM was up mid-teens, driven by strength in the semiconductor and data center markets. Construction was up low double digits, supported by robust wire and cable demand and continued infrastructure project activity. Industrial was down low single digits, primarily reflecting project timing impacts. However, our industrial stock and flow business grew mid-single digits in the first quarter, and backlog was up double digits, supporting an improving trend. Data center sales in EES were up over 100% year-over-year and represented about 10% of EES sales, highlighting the continued scaling of our exposure to this secular growth trend. Overall, organic growth was driven by solid underlying demand, with volume contributing approximately 3% and pricing contributing about 4%.
Importantly, backlog ended the quarter at a record level, up 14% versus the prior year, supported by strong order activity and pipeline conversion. Profitability improved meaningfully in the quarter. Adjusted EBITDA increased 30% to $185 million, and adjusted EBITDA margin expanded 130 basis points to 8.2%, driven by higher gross margins and strong operating leverage. Turning to Slide 8, UBS delivered 6% organic sales growth in the first quarter, supported by improving demand and an increasing backlog. Utility delivered high single-digit growth, driven by strong double-digit growth in investor-owned utilities and continued positive momentum in grid services. Public power was flat year-over-year, which is encouraging. However, the market remains highly competitive and gross margins are expected to remain under pressure given weak sales and transformers and wire and cable, consistent with our prior commentary.
Broadband delivered mid-single digit growth year-over-year, supported by strength in the U.S. Overall, organic sales growth reflected approximately 3% volume growth and about 3% pricing. Backlog increased 16% year-over-year. We are seeing increasing interest in our grid services-enabled power capabilities from hyperscalers and other data center customers. We have a growing funnel of sales opportunities. We are bullish that we will benefit from AI-driven data center investments and other major power-related infrastructure projects over the long term. Adjusted EBITDA was $131 million, down 5% versus the prior year. Adjusted EBITDA margin decreased 120 basis points to 9.6%, primarily driven by gross margin pressure and higher SG&A as a percentage of sales.
Recall that UBS is accretive to total company-adjusted EBITDA margin given its higher margin profile, and the improved growth rates will lead to even higher margins over time given the operating leverage. Turning to Slide 9, I wanna take a moment to further review the continued momentum we're seeing in the broader data center market and Wesco's role in that growth. Data center sales continued to scale in the first quarter, reaching approximately $1.4 billion, up about 70% year-over-year, and representing 24% of total company sales in the quarter. Notably, the data center end market is now Wesco's largest end market across all three SBUs and support a diverse set of customers with a diverse set of Wesco capabilities. On a trailing 12-month basis, data center sales are now approximately $4.8 billion or 20% of Wesco's total sales.
This underscores both the strength of the secular demand environment and the expanding scope of what we provide customers across all business units and across the full life cycle. Turning to Slide 10, this highlights our end-to-end data center offering and the role we play across the full life cycle with exposure across CSS, EES, and UBS. Wesco supports hyperscale, multi-tenant, colocation, and enterprise customers with a comprehensive portfolio of products, services, and solutions that span power, connectivity, and ongoing operations. Our expanding capabilities and global ecosystem position us as a trusted partner as customers build, scale, and operate increasingly complex data center environments. Turning to Slide 11, we delivered strong free cash flow of $213 million in the first quarter. Free cash flow was 128% of adjusted net income.
Despite sequential sales growth, net working capital was a source of cash in the quarter, largely driven by timing of inventory purchases and accounts payable. Moving to Slide 12. During the quarter, we executed a highly successful $1.5 billion bond refinancing that was upsized relative to the initial launch, reflecting strong investor demand and record pricing. Notably, we achieved the lowest coupon Wesco has ever achieved on a senior notes offering and the lowest for a BB-rated five-year note issued since 2021. The net proceeds will be used to redeem our 2028 senior notes, improve liquidity, and further strengthen the balance sheet. This refinancing meaningfully improves our debt maturity profile and is expected to generate more than $20 million in annualized interest expense savings. We exited the quarter at 3.2 x net debt to adjusted EBITDA.
Additionally, we repurchased $25 million of shares during the quarter towards offsetting dilution. Moving to Slide 13. Within CSS, we have raised our 2026 outlook to low double-digit growth, reflecting the continued strength and visibility we are seeing in data centers. Data center sales are now expected to be up 20%+ for the year. Given the size of the market, we intend to continue to focus on healthy EBITDA margin business. Our outlook for EES and UBS remains unchanged. Moving to Slide 14, we are increasing our outlook for the full year given strong first quarter results. Before I get into the details, I want to address our position relative to the current macroeconomic uncertainty. Through the first quarter and into April, we have seen no meaningful disruption to our revenue or profitability.
We continue to monitor the situation closely and kept this backdrop in mind for our outlook. In the Middle East, I am pleased to report that all of our employees are safe. From a company perspective, we generate less than 1% of our sales in the region, with the majority of those sales related to our CSS business. The secondary impacts on transportation costs are more tangible but have so far been manageable. Our teams are focused on passing these cost increases to our customers where appropriate and limiting the time that transportation quotes are valid to minimize overall risk. On the tariff front, the overall impact to Wesco is not material. As a reminder, Wesco is the importer of record for a small percentage of our cost of goods sold, typically low single digits. We typically increase prices when needed to maintain margins.
At this point, we don't expect any material recoveries from the IEEPA decision. Based on the strong start to the year, we are raising our full year 2026 outlook. We now expect reported sales growth of 6%-9% with organic sales growth of 5%-8%, which implies reported sales of approximately $24.9 billion-$25.6 billion. Our assumptions around foreign exchange and pricing remain unchanged. On profitability, we continue to expect adjusted EBITDA margin in the range of 6.6%-7%, essentially increasing our EBITDA guidance in dollar terms. We are raising our adjusted diluted EPS outlook to $15-$17 per share, reflecting earnings leverage demonstrated in the first quarter as well as slight adjustments to the expected tax rate for the year.
There is no change to our outlook on interest expense based on our current view of no rate cuts this year and factoring in timing of the debt raise and subsequent paydown. Finally, we continue to expect free cash flow of $500 million-$800 million as we maintain working capital discipline supporting higher growth. As a reminder, our historical pattern is typically about 70% of our annual cash flow is generated in the second half of the year. Turning to Slide 15. While April is not entirely closed out, month- to- date, sales per workday are up about 10% year-over-year, with growth continuing to be led by CSS. For the quarter, we expect reported sales to be up high single digits.
Recall that more than 50% of our sales are related to project activity, and the mix of project sales is higher in the second and third quarter due to increased construction activity. The timing of project billings at the end of the quarter will determine where we land in the high single-digit range. On margins, second quarter EBITDA margin is expected to be about flat year-over-year and within our full year guidance range. Higher incentive compensation, approximately 25 basis points, accounts for most of the year-over-year pressure, and we continue to expect double-digit growth in adjusted EPS. As you think about our outlook, keep in mind that we had strong sales growth and good EBITDA margins in second, third, and fourth quarter of last year. On a two-year stacked basis, growth is expected to remain strong and consistent with the outlook we've provided.
We've covered a lot of material this morning, so let me briefly recap the key points before we open the call to your questions. In summary, we delivered an excellent start to the year with double-digit sales growth, margin expansion, and over 50% EPS growth. AI-driven data centers and related investments from our customers remain a key driver of growth across several product categories and verticals. We generated strong cash flow and improved our leverage and debt maturity profile during the quarter. Despite macroeconomic uncertainty, we are confident in our positive business momentum and are raising our full year outlook. As we lean in to support organic growth, there is no change to our previously communicated capital allocation priorities and guiding principles. With that, operator, we can now open the call to questions.
Thank you. We will now begin the question and answer session. If you would like to ask a question, please press star followed by one on your telephone keypad. Please limit your questions to one question and one follow-up. Our first question today comes from David Manthey with Baird. Please go ahead.
All right. Thank you. Good morning, guys.
Morning, Dave.
Yeah, good morning, John. CSS doing amazing, I'll focus on EES and UBS with my questions first thing here. First on lead times. I know within the industrial business, you mentioned project timing as the reason for that small decline there. With switchgear components stretching well over one year and medium voltage switchgear sometimes staying 40, 60 week lead times, you're clearly navigating any shortages in the market out there well overall. Could you just talk about the specific issues? Where are the pinch points? Is that what you mean by project timing?
Great question, David, and your lead times comments are accurate. We're still seeing extended lead times in two critical categories. Honestly, we've been facing those extended lead times since the pandemic, and we've been managing the business well. I think this is just more of a very specific intra-quarter project timing issue. I'll give you my views of industrial. I've mentioned this before, I know. I really believe we're at the beginning of an industrial super cycle. In the U.S., in particular, it's driven by AI-driven infrastructure investments. Clearly, the need for increased power generation, not just for AI data centers, but for all these mega projects, and a fundamental secular trend that I think is becoming more apparent every day regarding reshoring.
These secular trends are gonna play out over many years, and they really expand Wesco's opportunity set. Specifically relative to your question in Q1, I'd ask you to look at kind of our short cycle business. Neil highlighted it in his commentary. Our industrial stock and flow, the short cycle business, MRO supplies and such, that was up in line. Mid-single-digit growth with recent recovery in industrial production. That's really a good important leading indicator. It was offset for us with some project timing issues. Relative to the project timing issues, however, our book-to-bills were exceptionally strong in EES and particularly in industrial in the first quarter. We have double-digit backlog growth in the industrial portion of EES. That supports a future improving trend for industrial. Again, consistent with my overall views of the cycle.
Yep. Thanks for that, John.
Yeah.
I agree. Maybe I could ask Neil, you know, from the first conversation that you and I had, I get the impression that you're a deal guy at heart. Could you just discuss, as you settle in here, how you find the Wesco M&A process and what you think about the pipeline, your general thoughts on consolidation going forward?
Dave. You know, I think, from Wesco perspective, as I've spent a lot of time on the operations, one thing I would mention, I'm more of an operations guy than a deal guy, first of all. But I do like to get into the operations side of deals. I would say we have a great team here evaluating deals. We're gonna be very active, but also very disciplined, right? We wanna make sure that there is fit in terms of our strategy and where we wanna take the business. We wanna play into a lot of the megatrends that we are seeing in the marketplace, right?
It's all about how a deal accelerates our overall growth and profitability and, you know, not just something that we would buy to leave standalone. Like we've talked about, Dave, like the margin profile is another real important driver for us. We're very focused on it. We've launched a number of initiatives on that front. M&A will be another lever. Dave, just one thing back on your earlier question, not specific to EES and UBS, but I came from the infrastructure side, building a lot of infrastructure. One of the things that right now we see, prior to my role at here, and we will see some of the secondary effects here, is the throttling factor for building infrastructure really are two things: lead time and skilled labor.
That's been true for a number of years and will continue to be true going forward, right? It's not the appetite for investment, it's not the allocation of capital, it's really those two things that's calibrating the spend quarter-over-quarter from a customer's perspective, not our perspective.
Mm-hmm. All right. I appreciate your thoughts, Neil. Thank you. And thanks, John.
Thanks, Dave.
The next question comes from Deane Dray with RBC Capital Markets. Please go ahead.
Hi, this is Kenny Seaman for Deane Dray. I did wanna ask you about data center. Can you unpack the data center strength given you're clearly outperforming the peers here? You know, where are you gaining share of wallet? You know, how's the growth rate different across the gray space, white space, and services? Maybe a related question to that is, what's driving the step down in data center growth rate in the back half in your guidance? Thank you.
Yeah, good morning. We've outlined white space, gray space growth rates. Again, white space ostensibly you know, supported and provided by our CSS business deep roots go back into legacy Anixter. Again, they've been a data center business for decades. That grew north of 60% in the quarter, very, and is the driver of the backlog growth in CSS, a major driver. Very strong growth rates in white space. Services are embedded in that. We don't break that out separately. For the gray space ostensibly served by EES, that was up over 100% in the quarter. Again, services are baked into that. Yeah, we're very confident that we're outperforming the market meaningfully. Again, we're uniquely positioned with our portfolio because we have the datacom related solutions a la white space with CSS.
We have the core electrical infrastructure solutions and connectivity solutions, a la, supported by our EES business, and we have the power solutions supported by our UBS business, which is our grid services in particular that's tucked in under our UBS business. Relative to the outlook, look, we took investors through that when we provided our full year guide. We think it was appropriate originally. We obviously have stepped it up meaningfully now given this exceptional start to Q1.
Thank you. I appreciate that. Just on sticking with CSS, another really good double-digit increment of margins for this segment this quarter. Just curious what needs to happen for this double-digit increment of margins to be, you know, sustainable and potentially move towards the mid-teens given you're still executing on these large projects?
Look, we've been very clear on how we're managing that business. First let me say, and I've gotta say this, we have a new CSS leader. He's been at the helm now kind of four quarters. He took the business that had positive momentum, clearly, four quarters ago, and he's accelerated that momentum and stepped up the performance meaningfully. I think you see that in the results. We are very aggressively managing our gross margins, and you can see that they remain stable. Obviously, we're trying to expand gross margins too, and we'd love to do that over time. We've got stable gross margins in CSS, and we have outstanding operating cost leverage. That's what I really wanted to highlight to you. To be at 9% EBITDA for Q1, we're thrilled with that, quite frankly.
It's a huge step up. We've been north of a 9 handle on EBITDA margins more than one quarter in a row. We had it in Q4 as well. I think you're seeing the power of our portfolio, our execution, and the inherent operating leverage in our business model showing up in the EBITDA expansion for CSS. It's very consistent with how we run the business. Again, I'll summarize, very focused on gross margins. If we can get every single basis point matters, so we'd love to increase it by as many basis points as we can. We absolutely will ensure the operating cost leverage. You know, we've got very good, strong top-line momentum. I'll also say that the backlog is an all-time record level, growing at 40%.
That's well in excess of our first quarter sales growth rate. As a side note, the backlog growth for all three businesses and segments was well in excess of our first quarter sales rates for each of the three SBUs.
Appreciate that. Thank you.
The next question comes from Sam Darkatsh with Raymond James. Please go ahead.
Good morning, John. Good morning, Neil. How are you?
Good. Good, Sam. How are you?
I'm well. Thank you for asking. Two questions, and I apologize if this was covered since I got temporarily dropped there for a second. It looks like, Slide 15, looks like April is coming in maybe better than March. The comparisons year-over-year are pretty similar, and you're saying April's up 10%. Can you give a little color maybe in terms of what you're seeing, John, in April? I'm really getting at the fact that are you seeing it in stock and flow improving over the last month or two, or is that just timing of projects?
Yeah, good question, Sam. First I'd say kinda mix. We're seeing the consistent mix of what we've had in the first quarter. I do wanna highlight, we still have two days to go. We actually are in the last day, you know, but by the time we see the final numbers for yesterday, I'm sure they're out now, but we're in the middle of our call. We have today, which will close the quarter. I will say that we are a very strong book-to-bill rates continuing. Again, mix consistent with Q1. If you look at Q1, you know, we had very nice stock-based sales momentum. It isn't, you know. Obviously, projects kicked in very nicely.
As I, like, relative to my comments on EES Industrial, you know, we actually had very good stock and flow momentum there. It was the project timing that resulted in that not being a, you know, a net growth in Q1. I feel good about our stock momentum, Sam. I'll just make that comment. I know you're kind of poking at that a bit.
Thank you. The second question, I think there was a recent presidential determination that authorizes federal purchasing and financing for the electrical grid. How material might this be for you, and when or where would it materialize first?
First, let me say, I think there, you know, various associations we're part of have all been working across the industry and with their industry partners and association members, of which we're a participant in really, you know, working proactively with the federal government on addressing the core issues around, you know, supporting this infrastructure build-out in the U.S. The biggest driver really is power and the power chain piece of that. We would see that, Sam Darkatsh, being supportive of what I see as fundamentally secular growth trends in utility. I've made a strong statement that utility was classically a cyclical industry and has now moved secular growth. Even though we're not seeing that manifest in all the numbers yet, we would see it in our UBS business, we would see it in our EES business.
Supportive of the secular trends.
Thank you much.
The next question comes from Guy Hardwick with Barclays. Please go ahead.
Hi, good morning. John, I wanted to just click on the that point you brought up earlier about backlog growing faster than sales in Q1. Organic sales up 12%, backlog up 22%. At what point does the sales catch up with backlog or does backlog really underpin, you know, 2027 revenues? I think, 'cause I think you said that they're lengthening somewhat.
Yeah. Yeah, it's a great question, Guy. Good morning, by the way. I think, you know, again, backlog only represents a piece of our business. We've said this before, long-term multi-year alliance agreements for utility customers, multi-year national account, global account agreements in industrial. There's also some in CSS. They don't all get loaded in the backlog because we're loading in the actual POs. We may have a multi-year agreement. We're only loading in the POs when we get the POs. With that said, we've been reporting consistently the trend on backlog. The fact that that growth rate is materially higher than our sales growth rate, that bodes well for, you know, this balance of 2026. It's also a look into 2027, which is the heart of your question.
You know, when you look at the projects that are in the backlog, you know, a number of them also ship in 2027, and there's some longer lead items that, you know, we're quoting, you know, for 2027, 2028. You know, like some transformer business and utility. It's, I'd ask you to kind of think about that just as the trend, the relative growth rate of that versus sales, and it speaks to, you know, kind of the rising demand curve that our portfolio is capturing.
Just to follow up, the 14% backlog growth in EES, which is the fastest in three years. I was just wondering how much of that was driven by data center projects.
We haven't disclosed that number. We haven't shared it, but think about the math here for a minute. You know, data centers for the gray space, EES' exposure to data centers was up 100% year-over-year, but it's only 10% of EES' sales. I would. You should think about that 14% as being a very, to your point, Guy, a very healthy number for EES overall. You know, here's a case where, and I got to make the comment now, it's actually pretty important. You know, two of our three SBU leaders are new in their jobs in the last year. CSS, we promoted from within four quarters ago. EES, we went outside and hired a leader. He returned to the electrical industry.
He's now been at the helm for three quarters, he is off to an outstanding start, as is our CSS leader, as I mentioned earlier. Look at the momentum vector and the profit quality improvement of EES starting in Q3 last year, Q4, and now Q1. This is his third quarter since he's joined us. You know, it's a big deal to have two of your three business leaders, you know, new in the saddle in the last year. I think we're seeing stepped up execution in both of those businesses.
Thank you.
The next question comes from Christopher Glynn with Oppenheimer. Please go ahead.
Thanks. Good morning. Exciting start to the year here. Just wanted to feed off that last topic. You were going into the EES margin trends and some of the execution there. The gross margin clearly sequentially has been really strong trend and now year-over-year standing out and, you know, nice outperformance on the EBITDA margin this quarter, particularly from a normal kind of sequential seasonal pattern that was long seen. I think the normal seasonality of the 2Q profitability ramp from EES is sort of downplayed and the suggested enterprise margin for the second quarter.
Just curious if kind of the seasonal margin swings, if you are seeing those level off, and that is sort of moderating the kind of 2Q forecast over the first quarter given that the baseline shifted upward in the first quarter.
First, let me comment on EES specifically. Again, we're not, we're not guiding gross margins or op margins by SBU for Q2. You know, we don't guide at that level. Neil will make a comment on EBITDA margins overall for Q2, because I think that's what you're kind of poking at. Again, back to the new leader effect. You know, when you have a new leader, takes a look at the business, looks at every potential lever. There's a very strong focus on profitable growth, stepping up the top-line growth rate. I think we're seeing that at EES, that's priority one. The other priority one or two equal number one priorities is to make sure we're getting inherently good margin expansion. We're confident we'll get the operating cost leverage, Chris.
You know how our business model works. When we get the sales growth, we're very disciplined around managing the SG&A leverage and ensuring the pull-through on the sales growth. There's been a particular emphasis and focus on looking at all margin improvement levers in EES over the last three quarters by our new leader and his team. We're making very good progress. This was a very encouraging start in terms of the profit quality of EES. Relative to our overall outlook of flattish EBITDA margins for the enterprise in Q2, there's some interesting timing dynamics when you look at sequentials that I'll hand it to Neil to take you through.
Sure. Thanks, John. Chris, I think, few things to highlight. One is, I said it in my prepared remarks, if you look at our incentive comp and performance last year versus this year, that was about 25 basis points of overall, 25-30, call it, of overall headwind in terms of in EBITDA margin at an enterprise level. That's one of the drivers. If you think about it sequentially, typically we see step down in revenue fourth quarter to first quarter. We had a lot of the old, you know, operating leverage that you see in the business in terms of sequential improvement in EBITDA margin that was accelerated into first quarter of this year. Sequentially, the, you know, improvement is a little muted.
Couple of other things to highlight. One is, you know, we are in an inflationary environment, but I would say we're doing a pretty good job managing that, and we're trying to pass that along to customers where appropriate, where the market will bear. That's a factor. One other thing is that if you look at the growth of our data center business, we are making some investments, very disciplined in facility expansion and capability expansions that shows up on our cost side. Those are, think about it as, you know, small step function investments, but we'll see the benefit for those over several quarters. And we'll see the operating leverage from that investment. That also mutes a little bit of the margin expansion year-over-year.
Great color. Thanks. Yeah, I think I'll leave it there. Well, actually one on WDCS. I think you mentioned that's now mixed accretive in CSS. Just kind of, you know, curious, maybe, double-click on that. I imagine if we look at your historical top five to 10 suppliers, for Wesco, that there's probably been some swapping there as WDCS has ramped so prolifically. Wondering if there's anything kind of interesting in that bank.
Yeah, Neil had in his prepared remarks, we thought it was very important for our investors to understand that WDCS, this exceptional growth we're getting and the way we're managing the margin profile of the business we're taking on, we're being very judicious in terms of what we bid, and then we're applying our value proposition to these customer opportunities, we are getting very good margin pull-through. It's quote-unquote accretive, as Neil outlined to CSS, which is very encouraging because that's, again, this strong secular growth trend and the exceptional growth we're getting there. It's a very positive driver. Chris, we have had some movement in the top five, 10, five to 10 suppliers for overall Wesco. I'm not gonna go through that in this call, you know, clearly we have.
You just look at the growth rates of CSS. A number of those, you know, suppliers are experiencing meaningfully greater growth than some of the, some of our other suppliers. With that said, you know, because look at our overall momentum vector as the company. This is the third quarter in a row for the overall Wesco enterprise of double-digit growth. That's really terrific to see, and I think the rising tide we're creating with our suppliers is raising a number of their boats.
Was there a follow-up, Mr. Glynn?
No. Sorry. Just taking all that down. Appreciate the color and talk soon. Thanks.
Thanks. Thanks, Chris.
The next question comes from Ken Newman with KeyBanc Capital Markets. Please go ahead.
Hey, thanks. Morning, guys. Indraneel .
Morning, Ken.
Welcome to the team and looking forward to working with you. Morning, John.
Thanks, Ken.
Yeah, no problem. Maybe, just for my first question, just thinking about the pricing side that you had this quarter, the 3% net price. Can you help us just quantify, you know, just how much of that was from carryover benefits from last year versus incremental pricing that I know wasn't baked into the outlook? Then just any color that you're seeing from supplier pushes on pricing as we exited the quarter.
Ken, I think most of that is carryover benefit. Because if you think about the timing of when we get the notices and the actual yield and what flows through into the financials, I would say most of that is carryover carryover benefit. Couple of things to keep in mind is, you know, as you think about the business going forward, CSS is our largest business unit right now, right? Which the price impact has been, you know, small compared to the other two business unit. Increasingly, we're doing a lot of projects where the pricing is negotiated with special pricing agreements. Just a comment to keep in mind as you think about our outlook going forward.
Understood. For the follow-up, you know, is obviously really strong growth in data center, particularly in the white space side. You know, I'm trying to maybe contextualize what you saw in the gray space versus the white space. If you could just talk about how much of the white space growth this quarter you saw was maybe a translation or a transition from projects you won in gray space a few years ago. You know, how do we think about the potential of that 100% growth in gray space this quarter, maybe transitioning for white space activity over the next 12-18 months.
It's, it's a very good question. I would tell you that, you know, we're working the one Wesco solution, which is obviously on all future bid opportunities. It may be just for a portion of the white space, it may be a portion of the gray space. It could be uniquely for a piece of the power solution with UBS. We're pulling in all three SBUs, and even irrespective of what the RFP is for, we're going in with our full value prop saying, "Look, okay, we'll bid the RFP, but look at all the other things we can do with you, do for you." I think that has excellent momentum, Ken.
In terms of your specific question, the EES growth we got, the majority of that we got in Q1 was not linked to a prior CSS or white space win. Not. You know, if you look at how the market fundamentally works today, the natural market procures gray space and white space at different part times of the build cycle, and power altogether is addressed differently, much earlier in the build cycle, and by different people making those decisions. What does that mean for our mix?
What that means for our mix in the, in the, you know, in the real-time basis is we're not seeing a lot of that linkage yet, but we clearly are putting shots on goal with our broader value proposition, and we're very confident that that has huge needle-moving potential for the overall Wesco going forward as we aggressively go after this secular trend. Again, I couldn't be more pleased with the 100% growth in gray space in Q1 for EES. That just shows that we're putting an awful lot of shots on goal. Again, it's, you know, just roughly 20% of our overall sales mix, but still very encouraging growth rate.
Just one minor point, Ken, to add to John.
As a new guy coming in, I've been super impressed in terms of the coordinated effort that we have across all three SBUs in terms of our go-to-market effort on the data center side. We really go to market as one Wesco across all three SBUs, across the white and gray space, but every customer buys differently and we let the customer decide in terms of where our value proposition resonates or not.
Very helpful. Appreciate it.
The last question today will be from Patrick Baumann with JPMorgan. Please go ahead.
Good morning.
Morning, Patrick.
I had one quickly. Maybe not quickly, I don't know, it's up to you. On digital transformation. It seems like those costs are stepping up here in the first quarter in terms of, you know, what's outside the P&L. I guess a couple questions here. What are you spending that on? Like, what are those costs for? What's the path and timing of the ERP rollout? Can you talk to your confidence and execution on that? You know, what happens to those costs, you know, on day one when those ERP systems turn on? How long does it take you to realize the benefits of this plan? I know there's a lot there, I'll leave it to you to see how you want to answer it.
Well, well, well, let me first say that our last fulsome update was at our Investor Day year before last. We outlined that program, and we laid out, you know, still, at that point, extensive activities remaining for design build. We had not really begun deployment in any form or fashion at that point. We've not given a fulsome update, which we will do next time we have our next Investor Day. At least I'll address your question by saying outstanding progress on the design build. We continue to grind away at that. Our resources are focused on that. We've begun deployment. This is a really important point.
We have a very small number of locations in each of the three businesses that have been deployed, and that's been part of our agile design and build process, and increasing capabilities being brought to bear in our design build that we're, you know, releasing and deploying in those various locations. We had a notable milestone in the first quarter where we have one operation, one P&L operation, end-to-end P&L operation as part of CSS that's been fully deployed on our new digital platform. That occurred literally at the very end of the first quarter. Now we have an end-to-end operation with the latest instance that has the most capabilities deployed to date.
We still have design build activities that continue through the, you know, through this year, and into, in the beginning part of next year, but then our deployment starts to phase in and accelerate completely consistent with what we outlined at our Investor Day. It's a phased deployment. Unlike an ERP transition, where it's a knife-edge switch and you put the enterprise at risk, we control the phasing of the deployment to make sure that, you know, we don't disrupt the business and we can manage the change management associated with the deployment. In addition, it's of our utmost priority that we do not disrupt our current business momentum. We have excellent, improving positive business momentum, and we wanna make sure that we execute against that, as evidenced by our first quarter results.
Let's just be very clear, that's our priority. Again, we'll have a phased deployment. No change to kind of program design build deployment schema. Huge milestone in Q1 where we have one end-to-end P&L operation now deployed, and we're seeing how that's operating. The benefits will phase in over a multi-year period, similar to what we outlined at our Investor Day, where we said it's a two-speed margin improvement profile going forward, EBITDA margin profile. We're grinding away to get operating margin expansion as we complete design build and deployment. Once that's complete, there's a step function increase in the margin expansion because all the one-time investments are done. Very much looking forward to those benefits. Again, they're not hitting our P&L at all yet, so that's all futures. That's to come.
Thanks for that.
On your question, Pat, on your question on, like the disclosures, obviously we provide a fair amount of disclosure in terms of what's excluded from EBITDA, going from EBITDA to adjusted EBITDA. Just like most company, the objective is to really give you visibility to things that, like John mentioned, are one time in nature. Yeah, we'll reevaluate that every year when we do our reporting, but you got full visibility.
Thanks for that. My last question I just wanted to touch on, which it was asked earlier in the call, but just bear with me on this. Your data center revenue in the quarter was $1.4 billion. You know, you annualize that, you're at $5.6 billion. I think that's, that would be up kind of 30% versus what you reported last year. You know, in the quarter you're up 70%. You have hyperscaler CapEx that's going up 70% this year. Help us kind of understand what tails off. Is it, you know, some big projects or jobs that, you know, that top out in the first quarter? 'Cause the 20% growth just seems like.
It's great, in context of what you've been putting up, it's something, seems like, you know, maybe it's, you know, project timing. I don't know. If you could help us understand that.
We addressed it earlier in the call, and you gave it the answer in the last part of your question.
Project timing.
That's that is the answer. Again, look, we had a lot of questions when we gave our initial outlook for 2026 when we reported our Q4 results. We went, you know, we've taken all of you through that, kind of our views on this, and it was project timing then, it's project timing now. With that said, it's an exceptional start to Q1. We're thrilled with the start.
Thanks a lot. Best of luck.
This concludes our question and answer.
Okay. Thank you. I think we've addressed all your questions. We're gonna bring the call to a close. There's no one left in the queue, which is great. We've got a lot of calls lined up for today and tomorrow. We look forward to speaking with you in the follow-ups. Thank you all for your support. It's very much appreciated. We expect to announce our second quarter earnings on Thursday, July 30th. Have a great day.
The conference has now concluded. Thank you for attending today's presentation. You may now disconnect.