Good afternoon. Welcome to the Chewy second quarter 2021 earnings conference call. All participants will be in listen-only mode. Should you need assistance, please signal a conference specialist by pressing the star key followed by zero. After today's presentation, there will be an opportunity to ask questions. To ask a question, you may press star then one on your touch-tone phone. To withdraw your question, please press star then two. Please note this event is being recorded. I would now like to turn the conference over to Robert LaFleur, Vice President of Investor Relations. Please go ahead.
Thank you for joining us on the call today to discuss our second quarter 2021 results. Joining me today are Chewy CEO, Sumit Singh, and CFO, Mario Marte. Our earnings release and letter to shareholders, which were filed with the SEC earlier today, have been posted to the investor relations section of our website, investor.chewy.com. On our call today, we will be making forward-looking statements, including statements concerning Chewy's future prospects, financial results, business strategies, investments, industry trends, and our ability to successfully respond to business risks, including those related to the spread of COVID-19. Such statements are considered forward-looking statements under the Private Securities Litigation Reform Act of 1995 and are subject to certain risks and uncertainties, which could cause actual results to differ materially from those contemplated by our forward-looking statements. Reported results should not be considered an indication of future performance.
Also, note that the forward-looking statements on this call are based on information available to us as of today's date. We disclaim any obligation to update any forward-looking statements except as required by law. For further information, please refer to the risk factors and other information in Chewy's 10-Q and 8-K filed earlier today, and in our other filings with the SEC. Also, during this call, we will discuss certain non-GAAP financial measures. Reconciliations of these non-GAAP items to the most directly comparable GAAP financial measures are provided on our investor relations website and in today's SEC filings. These non-GAAP measures are not intended as a substitute for GAAP results. Additionally, unless otherwise noted, results discussed today refer to second quarter 2021, and all comparisons are accordingly against the second quarter of 2020. Finally, this call in its entirety is being webcast on our investor relations website.
A replay of this call will also be available on our IR website shortly. I'd now like to turn the call over to Sumit.
Thanks, Bob. Thanks to all of you for joining us on the call. We have now crossed the halfway point of 2021. Our results once again demonstrate the strength of our business model and the incredible bond between pets and pet parents. Our business remains healthy, customer engagement continues to grow. We are confident in our ability to build upon the strong results we delivered last year while navigating the uncertain market conditions due to the ever-evolving COVID-19 pandemic. Let's start with our second quarter results. Q2 net sales rose 27% to $2.16 billion. To gain an even greater appreciation of our top-line momentum, we believe it is also insightful to look at our net sales growth on a 2-year stack basis. Through this view, Q2 2021 net sales grew at a 2-year CAGR of 37%.
We ended Q2 with 20.1 million customers, a year-over-year increase of 21%, or 29% on a 2-year CAGR. Gross customer adds are running higher than pre-pandemic levels, below the record levels we saw last year during the peak of the pandemic-driven lockdowns. In fact, year-to-date, we have acquired approximately 20% more new customers than we did in the first half of 2019, prior to the pandemic. Our retention rates remain stable as well. In addition to the number of customers we add, customer spending is equally as important to our growth equation. Second quarter net sales per active customer, or Net PAC, increased 14% to $404. This is a meaningful acceleration over the growth we reported in the first quarter, the first time in the company's history that Net PAC has surpassed $400.
We have increased share of wallet from every cohort we've added to our platform over the past 10 years, and our long-term revenue retention levels from each cohort remain well above 100%. As a result, our base of recurring revenues grows over time as the revenue produced by each cohort stacks on top of one another, like the layers of a cake. Because revenue retention is above 100%, each new cohort's contribution to net sales is completely incremental to the base. This dynamic, combined with our ability to consistently improve margins, creates a powerful long-term growth and profitability flywheel. Returning to our second quarter results, gross margin expanded 200 basis points to 27.5%.
Driving 200 basis points of gross margin improvement in this difficult operating environment reflects our focused execution across multiple customer offerings and the strong and recurring purchase behaviors of our customers over time, combined with the benefits of our scale. The pricing and promotion environment remained stable throughout Q2, and we estimated that this benefited gross margins by approximately 50 basis points. As was the case across much of the economy, labor market challenges persisted throughout Q2. This impeded our ability to staff our FCs at desired levels and achieve optimal productivity. Aligned with the expectations we shared with you on previous earnings calls, we increased our investments in wages, benefits, and hiring incentives across our fulfillment network in order to maintain customer experience and business continuity. As a result of these increased investments, Q2 SG&A leverage was minimal. Marketing is an area where the landscape evolved rapidly in Q2.
The 80 basis point increase in advertising and marketing expenses as a percent of net sales in Q2 is the result of two main drivers. The first is the sharp recovery of input costs across advertising platforms. While this was expected to some degree, the magnitude of increase in Q2 was unprecedented. Second, seeing early signs of benefits from our continuous learning approach, we invested dollars into the opening of new marketing channels, which we believe will drive incremental long-term customer acquisition and build brand awareness. Usually, we see a couple of quarters lag between the initial investment in a new marketing channel and the realization of returns as those channels scale.
The Q2 gross margin gains that were driven by our strong operating performance more than offset the environmental challenges from higher FC labor costs and elevated marketing expenses, and Q2 adjusted EBITDA margin expanded 20 basis points to 1.1%, and adjusted EBITDA increased 51% to $23.3 million. Mario will provide more color to this line item. Next, I'm excited to share some of the many innovations we've been working on at Chewy. These initiatives are improving operational efficiency, driving higher customer engagement, and advancing sustainability. Collectively, we believe these efforts will unlock additional top-line growth and support long-term profitability. Let me start by updating you on the latest developments across our fulfillment network. We recently announced that our 14th fulfillment center and fourth automated FC will open near Nashville, Tennessee, in the fall of 2022.
Nashville now joins Kansas City and Reno in the pipeline of FCs that we will open over the next 12-14 months. Additional efficiency-driving measures include technology which custom-makes boxes based on the size of the contents. This process is not only faster than manual pack and ship, but it also reduces the amount of corrugate and packaging materials used per order, which then reduces costs and is better for the environment. We are also refining our pick, pack, and ship processes to reduce the time spent configuring box contents, which helps expedite how quickly packages leave our FCs. Collectively, once these three automated facilities and efficiency measures are fully ramped, we expect that increased fulfillment productivity will produce 40-60 basis points of incremental SG&A operating leverage and reduce our future exposure to labor market volatility.
We are also deploying new software across our FC network to improve productivity, reduce per-unit fulfillment costs, and positively impact sustainability. For example, in the second quarter, we launched proprietary machine learning-driven software which streamlines order routing and allocation across our growing FC network to optimize shipment volume, customer promise, and cost to fulfill. At our current scale, the fully realized benefits from this proprietary software are expected to be between 30 and 50 basis points of margin improvement. Once fully ramped across our FC network, we expect these initiatives to contribute a combined 70 to 110 basis points of incremental adjusted EBITDA margin. Moreover, these efforts have become increasingly relevant as labor markets remain challenged, transportation networks become capacity constrained, and inflationary pressures on freight costs begin to rise.
Moving on to Chewy Health, we continue to think big and innovate rapidly to serve our growing base of customers and veterinarian partners. First, we are very excited to launch a marketplace for veterinarians directly on chewy.com to help them grow clinic revenues and improve experience for pet parents. This revolutionary free service enables veterinarians to choose items to list on chewy.com, set prices, create pre-approved prescriptions, and earn revenue when customers place an order in-clinic or purchase from them via Chewy. Moreover, the service allows millions of Chewy customers to purchase pet medication directly from their veterinarian while shopping on chewy.com with fast, free shipping directly from our nationwide network of fulfillment centers. What is even more exciting is that the back-end prescription management capability of this platform is powered by our Vetscriptions product, which is currently in use at more than 8,000 clinics across the country.
Collectively, we are branding this innovative new platform as Practice Hub, through which we are offering veterinarians a complete e-commerce solution for their customers. Practice Hub leverages the benefits of our quick and reliable delivery, unparalleled customer care, and convenient Autoship subscription service. We look forward to sharing more details with you in our future earning calls. Second, we are pleased to announce that our third Chewy pharmacy will open later this year. This new facility, located in Pittston, Pennsylvania, will provide fulfillment services for pet medications and special dietary food, providing Chewy Health customers in the Northeast and Mid-Atlantic with even faster delivery of pet prescriptions and other health and wellness products. Last but not least, we continue to be pleased with the ramp of our compounding pharmacy service since its launch last fall. It is still early days, the results thus far are confirming our investment thesis.
Compounding net sales increased by almost 50% sequentially between Q1 and Q2 on increased order volume and larger basket sizes, and Autoship penetration increased over 250 basis points over the same period. More importantly, compounding is attracting new customers to Chewy Health, with 65% of new compounding customers either being new to Chewy entirely or existing Chewy customers who are first-time healthcare consumers. Services like compounding, which at the present moment are available only to our end customers, show how Chewy is uniquely positioned to assist pet parents who need customized solutions in an otherwise limited marketplace. Here at Chewy, we are pleased with and proud of our progress in the pet healthcare space. With every innovation that improves customer or vet experience, we progress one step closer to fulfilling our mission to make pet healthcare more affordable and accessible for every pet parent in the country.
We are doing so by keeping veterinarians at the center of the equation. Further, each new product or service that we launch to benefit our customers or vet partners further positions us as the only player in the pet industry who is building out a full pet healthcare ecosystem that effectively services both pet parents and veterinarians. In doing so, we are positioning ourselves to assume market leadership in the $35 billion TAM. Our pet health and wellness offerings from Chewy Health include OTC medicines, veterinary diet, pharmacy, compounding medication, telehealth, prescriptions, and now Practice Hub, a unique and innovative marketplace that provides the vet community a complete e-commerce solution that leverages all the strengths of chewy.com. More importantly, we are just getting started.
In addition to what we have shared today, we are working on multiple new initiatives across Chewy Health, and we look forward to sharing these with you in the not-too-distant future. Let's exit these innovation updates with a brief check-in on our newest launch, fresh prepared foods. Our expansion in the fresh and prepared food space continues as planned. The launch is still in the early days, and we are refining the product and service offerings based on customer feedback, keeping food safety and customer experience top of mind. Here are a few data points to apprise you of the ramp. We can now successfully ship product in custom-designed sustainable packaging to customers across 25 states, covering 56% of the U.S. population. Overall customer feedback is positive, and we continue to fine-tune our product and service offering based on this feedback.
Fresh and prepared Autoship sales as a percent of net sales are already approaching 50%. With fresh and prepared foods, we intend to deliver a customer experience that will rival how pet parents shop today by offering them a broad selection, great prices, and the unparalleled convenience and customer service that are Chewy's hallmark. I will conclude my remarks. We continue to execute our business plan with rigor and enthusiasm. Our fundamental growth drivers, expanding our customer base, increasing share of wallet, and building out our highly profitable verticals remain intact. We continue to drive year-over-year improvements in key metrics like net sales, gross margin, adjusted EBITDA margin, NSPAC, and free cash flow. Finally, amidst all the ongoing uncertainty, the Chewy team remains as relentless and customer-obsessed as ever, delivering new and exciting experiences to our pet parents and delivering top and bottom-line growth for our shareholders.
With that, I will now turn the call over to Mario.
Thank you, Sumit. I am happy to share our results as the execution of our long-term growth strategy continues to bear fruit. Beginning with our top-line results, second quarter net sales were $2.16 billion, representing 26.8% growth. On a two-year stack basis, Q2 2021 sales were $1 billion higher than the second quarter of 2019. Out-of-stock levels remained elevated in the second quarter, they improved modestly versus the first quarter, resulting in a smaller drag on net sales in Q2. This is a result of supply chain conditions improving in some areas as certain vendors reduce backlogs. Other areas like wet dog food are still being affected by industry-wide production capacity limitations. Second quarter Autoship customer sales increased 30.3% to $1.51 billion, or a 37.6% CAGR over the last two years.
Second quarter Autoship customer sales as a percentage of net sales increased 200 basis points to 70.3%. This improvement in Autoship penetration rate reflects maturation of the 2020 customer cohort and Autoship's growing value proposition. Active customers were 20.1 million at the end of Q2, an increase of 21.1% year-over-year. As a reminder, net customer adds are a function of new customers added in the period and the retention of customers acquired in prior periods. As Sumit mentioned, year-to-date gross customer adds are running 20% above the comparable pre-pandemic period in 2019, and retention rates are stable. To better demonstrate the dynamics of new customer adds and retention as they relate to net active customer adds, we have included a supplemental section on this topic in our shareholder letter this quarter. Second quarter net sales per active customer or NSPAC increased $48, or 13.5% to $404.
This was a $16 sequential increase over Q1. On an absolute dollar basis, both the year-over-year and sequential NSPAC increases were the largest in the company's history. We expect that NSPAC growth will remain strong for the balance of the year as the 2020 cohort continues to mature and we expand our customer offerings. Moving down the income statement, second quarter gross margin increased 200 basis points to 27.5%. Delivering 200 basis points of gross margin expansion in the current environment is a strong testament to our ability to scale our operations, increase share of wallet, and build a strong recurring revenue base by delivering best-in-class customer service to each and every pet parent. Second quarter operating expenses, which include SG&A and advertising and marketing, were $609.6 million, or 28.3% of net sales, compared to 27.4% in the second quarter 2020.
The increase reflects the incremental investments we made in both SG&A to overcome the current demand and supply imbalance in labor markets and in marketing. I will expand on both of these areas next. SG&A, which includes all fulfillment and customer service costs, credit card processing fees, corporate overhead, and share-based compensation, totaled $437.7 million in the second quarter, or 20.3% of net sales, compared to 20.2% in the second quarter of 2020. SG&A, excluding share-based compensation, totaled $412.1 million in the second quarter of 2021, or 19.1% of net sales, an increase of 110 basis points. This increase reflects the incremental $30 million we invested in wages, hiring incentives, and recruiting in the second quarter.
Not only was this budgeted spend in line with the Q2 expectations we outlined on our last earnings call, but it is also approximately twice as much as we spent on these items in the first quarter. Without this $30 million of additional labor expenses, second quarter SG&A, excluding share-based compensation, would have scaled 30 basis points year-over-year to 17.7% of net sales. Said differently, the permanent leverage in SG&A that we have delivered and expect to deliver in the future is being offset by temporary macro factors that are driving incremental costs. This demonstrates our ability to fund needed FC capacity and still leverage operating expenses. We believe that the investments we are making in our team members, automation, and technology will drive higher engagement, retention, and productivity, enabling us to effectively scale SG&A over the long term.
Second quarter advertising and marketing was $172 million, or 8% of net sales, an 80 basis point increase versus second quarter 2020. While we expected an increase in this line item, as add rates have been in an upward trend since bottoming out in early 2020, and organic customer growth rates have returned to pre-pandemic levels, the rate of increase we saw in Q2 was unprecedented, even for the seasonally strong quarter. As we enter the third quarter, add rates have moderated somewhat, but still remain above Q1 levels. It is worth noting that even with these two factors at play, when we take a two-year view, marketing spend in the second quarter scaled 160 basis points, while at the same time, we acquired more customers in the second quarter of this year than we did in second quarter 2019.
What this reflects is the efficacy of our marketing spend, which primarily focuses on acquiring and then developing customers to produce higher levels of profitable sales that increase the longer they stay with us. As a result, marketing scales as we grow. This, combined with improvements in gross margin, drives our LTV to CAC ratios over time. Second quarter net loss was $16.7 million, improving $16.1 million versus the second quarter of 2020, and net margin improved 110 basis points to a negative 0.8%. Adjusted EBITDA was $23.3 million, improving $7.8 million versus the second quarter of 2020, and adjusted EBITDA margin improved 20 basis points to 1.1%. As we have previously shared, we expect to make gradual and incremental improvement in profitability on an annual basis, while retaining the flexibility to make short-term investments in a given quarter for the long-term benefit of the company and our shareholders.
Moving on to free cash flow. Second quarter free cash flow was $60.3 million, reflecting $85.1 million in positive cash flow from operating activities and $24.8 million of capital expenditures. The positive operating cash in Q2 was primarily a function of favorable working capital, only partially offset by growth in our inventory levels as we work to protect our supply chain. Capital investments included additions to our fulfillment network, including cash outlays for our new FCs in Pennsylvania and Kansas City, as well as ongoing IT projects. We finished the quarter with $725 million of cash and cash equivalents on the balance sheet and no debt. In addition, we recently upsized our ABL facility to $500 million. This facility remains undrawn and combined with our cash on hand, provides us over $1.2 billion in available liquidity.
That concludes my second quarter recap, so now let's discuss our third quarter and full year guidance. Environmental crosscurrents continue to make precision forecasting difficult. Macro conditions seem to be improving as vaccination levels increase, although the Delta variant is clouding that picture. At the same time, supply chain and labor market challenges remain, and no one really knows how long or to what extent these might prevail. Still, there's a lot to be bullish about as the trends toward increased pet ownership, higher per pet spending, and category shift towards online all remain positive. Consumers may have started redirecting some of their discretionary spending back to areas like travel or dining out, but on the whole, spending on the family pet isn't really discretionary.
While there may be a few less indulgences on treats and toys as we return to the office, and some consumers might cross-shop more as they venture out and about, we don't believe that is going to alter the long-term trajectory of the pet category's ongoing shift towards greater online penetration. In fact, Chewy's growing product and service offerings, compelling value proposition, and unparalleled customer service have positioned us well to capitalize on the industry's expected growth and to keep gaining market share as sales continue to migrate online. Despite the elevated opacity of the current operating environment, we remain confident in our ability to deliver another year of strong top-line growth and adjusted EBITDA margin expansion. With that, we are reiterating our full year top and bottom line outlook as follows.
We expect third quarter net sales to be between $2.20 billion-$2.22 billion, representing 23%-25% year-over-year growth. We expect our full year 2021 net sales to be between $8.9 billion-$9.0 billion, representing 25%-26% year-over-year growth. Finally, we expect our full year 2021 adjusted EBITDA margin to expand between 80-120 basis points. As you update your models, please keep the following in mind. We still expect to add more new customers this year than we did in 2019, but not as many as we did during the pandemic last year. Normal attrition rates for a cohort as large as 2020 creates a meaningful headwind against net active customer adds this year. We expect this to be a one-year phenomenon, and the delta between gross and net adds is anticipated to normalize next year.
As I mentioned, we added a supplemental section on this topic to our shareholder letter this quarter. Please check that out for more details on the mechanics and math behind net active customer adds. Additionally, if the current labor shortages persist, they may lead to delays in orders leaving our FCs, similar to what we saw in the second quarter of last year, as demand surged and shipments lagged. This could affect reported net sales because we do not book the revenue from an order until it ships. To be clear, this simply affects the timing of when sales are recognized, as reported revenue shifts from one quarter into the next. Any potential inter-quarter revenue phasing is not incorporated into our current guidance, and improvements in the labor market could reduce or fully mitigate any risk.
As we continue to execute against our strategic plan of increasing scale, growing share of wallet, and expanding our product and service offerings, we remain focused on operational discipline and on driving meaningful margin expansion. Our 2021 guidance reflects net sales growth of 25% or better and adjusted EBITDA that is approximately 2x what we generated last year. We are delivering incremental profitability. At the same time, we are making meaningful investments in infrastructure that will support our growth, as evidenced by the fact that we will nearly double our fulfillment footprint in two years. In short, we are bullish about Chewy's future. With that, I'll turn the call over to the operator.
We will now begin the question and answer session. Our first question today comes from Stephanie Wissink with Jefferies.
Thank you. Good afternoon, everyone. We have two questions. One is more of a tactical question just on your comments on the wet food still being limited. If you could just talk a little bit about what you think that might have been as an impact to Q2 sales. Then maybe if you could talk a little bit about the NSPAC. It seems like it's coming in much stronger than we would have expected, even at this point in your maturation. Talk a little bit about how you're thinking about NSPAC contribution. I think you mentioned balance across net adds and NSPAC, but how are you thinking about NSPAC over the back half of the year and then maybe as we think about 2022? Thank you.
Hi, Steph. This is Sumit. I'll take the first one. Mario will take the second one. We estimate the impact to be lower than Q1 and in the range of $25 million-$30 million for wet food production.
Hey, Steph. This is Mario. I'll take the second part. NSPAC, you're right. The strength in NSPAC is meaningful. In fact, if you look at the $404 that we reported in the second quarter, and you look back sequentially and year-over-year, that is the fastest growth we've seen in dollar terms for that metric. Let me sort of give you color around what's happening around NSPAC. If we start with the cohort that joined us in the first half of 2020, since that's been a topic of conversation in the past. We now have at least one full year of data for that cohort.
Those customers now have a NSPAC in the following four quarters since joining of over $400. That's higher than cohorts in 2019 in the first year following their acquisition. What it tells us is that the hypothesis we had, that not only were those customers going to spend more upfront, but that their spend going forward would be higher, holds. Think about it in terms of the NSPAC curve that we've shared with you in the past. We believe that curve has shifted upwards for that cohort. That's very positive, right? We also had a hypothesis that, and we shared this with you last year, that the 2020 cohorts would develop LTV profiles that were as good, if not better than predecessor cohorts. So far, that's also proving out to be the case.
If we think about customer behavior more broadly, the average spend per new customer in the second quarter was higher than last year. The average spend per new customer in the quarter continues to rise year-over-year, and we've seen that trend in the last few quarters. Autoship sign-up rates remain strong, and they're running higher than last year, and the average basket size remain above pre-pandemic levels. The sales mix within our basket size is supporting the gross margin expansion. All those metrics and all those factors are helping in the various line items. Moreover, I think if we go back longer trend customer behavior, again, going back to what we shared with you in the past, remember that customer spend more the longer they stay with us. Those trends have repeated themselves year after year after year since our launch.
To give you an example of that, every cohort that we acquired in 2015 and prior to 2015 has a NSPAC in the last 12 months of over $800. Again, all the trends, all the metrics that we're seeing are still pointing in the right direction.
Very helpful. Thank you.
Our next question comes from Mark Mahaney with Evercore ISI.
Okay, thanks. Let me ask a couple, please. First is, you talk about leaning into some new marketing channels, but I don't think you described what those were. Any color on those?
Hey, Mark. This is Sumit. No, we haven't provided color on those, Mark. Just on the basis of sensitivity and information that we're still kind of experimenting and don't want released publicly at this point.
Oh, okay. Understood. Let me switch. These elevated costs you're seeing in labor and marketing, there's no particular reason why you have visibility into when those would change. As you think about it, to the extent to which they're temporary or permanent, I don't think there's a way to answer that, but do you have a strong point of view as to whether those elevated costs in both of those areas, are things that, are they permanent or is it, after 3 or 4 quarters, those should abate? Any opinion on that?
When you say both areas, you mean labor and which one is the second area?
Marketing, you talked about
Okay
rising adds costs.
I see. Marketing. Okay.
Price per ad.
Okay. Let me provide color on both. On labor, no, we don't have perfect visibility. What we are is, we're triangulating data across markets where we have fulfillment centers, and our forecast and the fill that we are getting as a result of that, both in terms of short-term and long-term fill rates. We've triangulated data to understand the impact of where the pandemic, or the Fed benefits have retained versus where they have expired, and the correlation to what labor inflow or increase they provided to us on an index basis. What we have seen so far, Mark, is that the states where pandemic or the Fed benefits have expired, have provided us somewhere between a 25%-35% improvement in labor fill rates. The data, it's empirical data, and we're triangulating across a couple of different sources. We are tracking it closely.
We don't have full confidence on how the situation might evolve, but we are waiting for labor markets to kind of reveal themselves in terms of data points a bit stronger over the next couple of weeks, so that we can move into Q3 in the appropriate manner. For now, we're maintaining the level of investments that we've committed, to make sure that there's business continuity and customer experience preservation in terms of managing our shipments. Coming to marketing. Marketing is an area where the landscape evolved rapidly in Q2. A part of this was expected in terms of add cost recovering and participation rates improving from all players online and retail. The rate, of course, as Mario mentioned, was unprecedented, and I'll give you a little bit of color there here in the next 1 minute.
What we really saw was overall shopper demand in the online, in pet category in Q2, was flat to slightly down on a 1 year-over-year basis. Before it started picking up again in towards the latter part of July, and that uptick has actually continued into August. Amidst flat to declining industry-level pet traffic, Chewy's traffic in Q2 approximately increased, or was up approximately 20 percentage point premium to the overall industry. That indicates both a healthy inflow of customers and it also indicates that we're actually gaining share as the year plays out. The online segment softness in Q2, we also saw directly correlated with May and June, which were the months where queries for travel, restaurants, local retailers were at 12-month high. Which makes sense, because customers were venturing out pre-Delta variant.
To counter this traffic decrease in online, and at the same time to incent consumers to revert to their pre-pandemic store shopping behavior, both retailers and e-tailers spent marketing dollars vigorously on paid channels and participated across Q2 promotional events. As a result of this behavior, we saw pricing inputs increase across the board. Just as a reference, Google CPCs climbed 51% year-to-date in pet supplies category, and Facebook's average add prices increased 47% year-over-year. In pet, we actually estimate CPMs increased over 80% year-over-year in these months. These have been the highest year-over-year increases that we've observed in this space. I'll exit by saying this. As we've alluded to before, we don't really spend to a predefined marketing budget. Instead, we let the returns and the LTV to CAC ratios guide our payback philosophies.
All in all, we believe we spent incremental 50 basis points, or $11 million higher than our internal forecast that could be attributed to these rising add costs. As we step out of Q2 into Q3, add costs have moderated, they are running below Q2 highs, and they're running above Q1 level at this point. That's sort of the sentiment as we move into Q2.
Thanks, sorry, one last quick question. Thanks a ton for that slide 17, page 17. I appreciate the simple math behind that. When in your shareholder letter, you talk about retention rates being consistent, that's the same thing as saying that the churn rates are relatively consistent, that you're using the same terminology there?
Yes. Yes, we are.
Okay. Thank you very much.
Yes.
Our next question comes from Doug Anmuth with JP Morgan.
Thanks for taking the questions. I have two. First, just on customer additions, would you still expect 2021 to return to pre-COVID or 2019 type of levels, which would suggest bigger sequential pickup in the back half? Is the composition of how you get to that key revenue a little bit customers somewhat below that, and then just the higher NSPAC that you're seeing. Secondly, Sumit, if you can talk a little bit about Chewy Practice Hub for vets. Curious on your view of how that opens up the addressable market for prescriptions, any early feedback you can provide from vet partners, and just what you've learned from the 8,000 clinics that you've been working with on the back end so far. Thanks.
Hey, Doug, I'll take the first part of the question, and then Sumit will address your second part. When you think about the active customer adds this year, and this is why we included a supplemental in the shareholder letter, is to show you the math behind it. I would expect the impact of the very large, I would say record-sized cohort in 2020 to still moderate or mask the number of adds we have this year. Said more plainly, I would expect our net active adds this year to continue to pace at a lower rate than we saw in 2019. Now, that is a one-year phenomenon. By next year, by 2022, we expect this very large cohort and the attrition that happens naturally in absolute terms to work itself through the cycle. Let's call it that.
On the flip side, what you have is NSPAC that is growing very quickly. That means that the customers that we're retaining and the customers we're acquiring are spending more and more on the platform. That's a very good sign. Not only have we acquired and are retaining a very large number of customers, in fact, adding more gross adds this year than we did in 2019, those customers are spending more and more with us over time. Those are very good dynamics that lead to expanding, growing top line, that lead to expanding gross margin because repeat orders are more profitable than 1st orders, and also lead to more efficiencies in the supply chain, and therefore a expanding bottom line as well. Those are good inputs in terms of NSPAC and active customer adds.
Okay. It's very clear.
Doug, I'll take the Practice Hub. This one we're very excited about. If you recall in previous earnings calls, I've shared that our research indicates 1/3 of pet parents do not take their pet to the vet or don't do so at a recurring frequency. Compliance is constrained or compressed in the industry. That actually holds back TAM. Secondly, this allows us to work with veterinarians more closely as direct partners, right? We've always been clear about the fact that we're building an ecosystem where the pet, the vet, and the pet parent are all very much in the center of the equation, and Chewy becomes an enabler to improve experience and complete that journey. Practice Hub essentially allows us to accomplish both, right?
Because veterinarians' offers are directly listed on chewy.com, the vets get access to 20+ million Chewy customers, and they also get the benefit and not only access to our powerful Autoship program, but they get the benefit on earning revenue on all repeat Autoship orders. It incentivizes improvement in compliance and working with a partner like us that actually understands customers and can build on those relationships from an education and awareness and driving repeat traffic point of view. With this type of a proposition, it just creates a lucrative flywheel for the veterinarians to be able to effectively participate, and it opens up both the marketplace for not only the vet or the TAM for the veterinarians to participate, but also consumers in the way that we will improve compliance. Your second part of the question was the exposure.
Today we're working across several independent clinics and also a very well-known, nationally recognized vet group who have so far been onboarded, and they're helping us perfect the product which is presently available on a curated and on an invite-only basis. As the year plays out, we are rapidly looking forward to working across the 8,000 clinics or 8,000 veterinarian practitioners that we have a partnership with who are already using prescriptions. Excited about what's to come next.
What's the timing for when you think this will be kind of fully open to all vets?
Yeah. We will have more to share, Doug, in Q3, but we are actively working with our vet partners, and we believe we will be fully ramped over the next couple of quarters here.
Okay, great. Thank you.
Our next question comes from Brian Fitzgerald with Wells Fargo.
Thanks, guys. I wanted to follow up on Doug's question, and it's in the mechanics of the Practice Hub marketplace. It sounds like it could evolve into a lead gen platform for vets eventually. Sumit, I think you mentioned a couple of days ago on the CNBC Evolve, you said, "Look, the tele-vet is acting as a triage." We're at a point right now where vets are being outpaced. Their capacity is being outpaced by demand, and so it almost acts like a triage situation. Is this a situation where you could eventually parlay this into a paid product for vets that's helping them get leads, that's helping them manage and triage things, and making them more productive to getting the type of work that they need to do, versus kind of sorting out stuff that really didn't demand a visit?
Hi, Brian. Yes, in short, we have a big, bold vision for what we can do with Practice Hub as we continue to develop and improve the product. We're starting out with the concept of a curated marketplace and backed by the power of prescriptions. Your intuition and the way that we're thinking big, yes, there are many ways that we're thinking about expanding the product and the service in the future.
If I can ask a quick question, do you have a rough figure for what percentage of the pharma business or the healthcare business is really akin to subscriptions like antiparasiticals, that heartworm pills show up every so often and have to keep giving them to the pet?
Our Autoship subscribe rate is equal or better in the pharma space. Is that what you were asking, or did I misinterpret your question?
Yeah. No, that's helpful. I wasn't sure what percentage of the TAM antiparasiticals make up of that $35 billion.
I see. Between heart and preventatives, it makes up 80% of the total $12 billion TAM that exists between OTC and pharma medication today.
Okay. Thanks.
Extreme pain medication and such makes up roughly 15%-20% of pharma.
Very helpful. Thank you.
Sure.
Our next question comes from Seth Basham with Wedbush Securities.
Thanks a lot, and good afternoon. My question is on your gross adds commentary. You talked about being up 20% year- to- date versus 2019. What's your expectation for the full year 2021 versus 2019?
Yeah, Seth, this is Mario. I'll take this one. Look, we know we don't guide to active customer adds in the year. I think the best way to think about the pacing is that the effect of the cohort that we acquired last year, you'll see that continue to have an impact, a masking of the gross adds we're adding this year. From a breaking down gross adds and active adds in 2020, 2021 that is, we don't do that.
Okay. Fair enough. Secondly, as it relates to the customers acquired in this second quarter, what type of LTV do you expect out of those customers versus the customers acquired the last year, given the record high CAC that I think that you guys were incurring this quarter?
I'll start again, and Sumit may add something to it. The LTV to CAC, you have to think about it in both terms. Yes, potentially there were some input costs that were higher in the second quarter, and therefore leading to a higher CAC, potentially, in the second quarter. The margin is amongst the highest we've ever recorded, at 27.5%. They're also spending more upfront. They've joined the platform and immediately started spending more, and the dollars they're producing at a higher margin level. There is an indication that the LTV to CAC should be in line with historical levels. I would say that.
The customer of today in the way that they're exposed to expanding and broad choices and offerings from us, which we've credibly expanded over the last three years. LTV expands by several hundred dollars on an annual basis. We haven't yet put a number to it, and it's hard because we're still graduating customers through different offerings that we've developed. Some of these offerings are early stages that we're actually maturing into. When you look at it from a maturity point of view, there's several hundred dollars of LTV to be added up top, which actually provides us a nice cushion at the expanding contribution margin to be able to tolerate CAC, and to be able to participate very effectively in the marketing environment, whether it be the marketing environment of today or the future as we continue to acquire more customers and add them to our platform.
Yeah. Very helpful. Thank you.
Our next question comes from Lauren Schenk with Morgan Stanley.
Hi, this is Nathan Feather on for Lauren. Can you just talk through a little bit more some of the puts and takes on gross margin expansion in the quarter, and where do you think that could have ended up without the short-term impacts in terms of discounting and other? Thank you.
Sure. Mario alluded to gross margin expansion, and we've provided the details in the script. Not much more to provide there. Customers continue to robustly engage across the verticals that we've built out. We continue to see our work in improving discovery search and graduating customers into buying more cross-category as well as higher margin verticals come to fruition. Combined with the benefits of our scale, is how we're driving the gross margin improvements. We estimated a 50 basis point uplift, or a 50 basis point addition to gross margin, as a result of the muted pricing environment or promotional environment that we're seeing currently.
Nathan, I would add that back to the point that Sumit made in the opening remarks, but we implemented technology, what we call the ORS 2.0, our order routing system, that we estimate could lead to another 30-50 basis points of gross margin expansion. There are puts and takes to gross margin expansion. We see the results in the second quarter. There's some initiatives that are in place that should expand that. Also, if you look at the mix of sales, consumable versus hard goods and other, there is opportunity to continue to move some of those sales to some of the more profitable mix in the future.
Okay, great. Thank you. On top of that, on the marketing side, did you see any shift in channels within the quarter in terms of where you're marketing outside of the introduction of some of those new channels? Was there any potential impact from IDFA in the quarter? Thank you.
Our marketing mix is dynamic, and we spend relative to the returns that we're getting. We don't have a predefined budget for a predefined channel or a fixed go-to-market strategy. It's a bit of a hard question to answer because depending upon the dynamic nature and the volatility that we saw in Q2, we reacted accordingly. What was the second part of your question?
Yeah, just did you see any impact from the Apple App Store change or the Apple fee changes IDFA?
Yeah, no, we've been actually working to mitigate that from the beginning in the way that our architecture is built. No, we didn't see a material impact on that so far.
Okay, great. Thank you.
Our next question comes from Peter Keith with Piper Sandler.
Hey, thanks. Good afternoon. Maybe follow up on the gross margin. Looks like you're seeing continued healthy mix shift. With all of the new engagement with pet health, I think in the past, you've talked about health running about 500-800 basis points above your core business. When we think about Practice Hub and compounding rolling in and presumably growing very quickly, does that gross margin lift change in any way, for better or for worse?
Sure. Sumit, I'll take it. We've said at scale, we expect healthcare to be 300-800 basis points higher gross margin than the base business. We're on track to deliver that. You can see some of that starting to come through in the gross margin uplift that we've continued to deliver on a year-over-year basis. Then, from here on out, as I've said in the past, we have many initiatives that we're working on to complete the roadmap that builds out towards our long-term guide of 25%-28%. So far, we've reserved the right to update that guidance because there's so much more interesting stuff for us to work on and reinvest dollars in where we see the long-term return taking place.
In terms of building out our roadmap, we have healthcare to build out that we are starting to open up more and be more candid with here and starting to share with all of you. We still have non-healthcare services to build out, and we still have a lot of work to do in connecting the dots to be able to engage the customer holistically across these three or four verticals that connect the pet life cycle. At the same time, we're thinking boldly about not just end consumers in the space, but also about the community that services pet, which is also embedded in our mission statement of being the destination for pet parents, but also partners. A few of the examples that you've seen us bring to life so far are compounding medications, which are today a B2C offering.
Now, with our telehealth, where we're working with veterinarians collectively, and now with Practice Hub, that we've actually opened up to veterinarians. You should continue to expect us to innovate robustly and at pace and keep you apprised of gross margin expansion in the future.
Okay. Very helpful. Separately, I was wondering if you could address the growth for small animal. I know dog and cat gets a lot of attention, but we've been hearing rumblings out there that it's actually small animal adoption that remains white hot. I was wondering if you're seeing that in your business, and maybe is it too small to matter or any quantification of sort of the ex-dog and cat business as a percent of sales would be helpful.
Yeah, your long-term trend is correct. Overall in the U.S., we believe somewhere between 30% and 40% of pets are small pets, and they are growing at slightly higher rate than large pets. It actually makes sense. A lot of Gen Zs and Millennials adopt pets, and at least pre-pandemic, city living and dwelling was continuing to become a popular option. When you look at the density of space and the 1 pet type that might be more suitable, it does give a little bit of a tailwind to the small pet data point. It's not materially shifting or has shifted to the point where we need to update our planning assumptions or educate customers a different way so far.
Okay. Thanks very much. Good luck.
Thank you.
Our next question comes from Chris Bottiglieri with Exane BNP Paribas.
Hey, thanks for taking the question. It was helpful to see the illustrative curves. I wanted to drill a little bit deeper. I think your overall consolidated attrition rate just naturally benefits from cohort maturation, just you have more overall customers, so it just naturally blends down, at least historically anyway. If you look at year 2 attrition rates in 2021 versus 2019, were the attrition rates better in 2021 than 2019? If you can comment, that would be helpful.
Chris, this is Mario. I'll take it. The attrition rate, no matter how we look at it, and we do look at it from many different angles, they've all remained within historical levels. It doesn't matter if we're looking at the 2020 cohort or if we're looking at the 2018 or 2015. The curve and the high levels of retention over time for those customer cohorts, almost regardless of the size of the cohort, remains steady. I think that's the best way to answer that.
Gotcha. Okay. That's helpful. Wanted to check in on the Freshpet offering, with your own private label product and then with Freshpet, you sell their products now. Can you give us a sense for what the early-- You gave us some growth rates, which was nice to see, but give us a sense, are you finding that your own customers are migrating up from kind of wet food and dry food into this? Are you conquesting new customers from other channels with this initiative? Just lastly, there's like a perception in the market that this might be lower contribution margin, just given the elevated shipping costs that go with this. What's your experience been so far from a contribution margin perspective? Is it similar to other consumables at the similar price point, or has it been diluted thus far? Thank you.
Sure. For the first part of the question, it's still a very new business, we're ramping it up with limited assortment so far. The customer base isn't large enough to have an interesting conversation so far. It is ramping very quickly. So far, we are seeing both. A lot of customers migrating, so existing Chewy customers either fully migrating or actually using these as a topper, which actually I will use again in the second part of your question. We're also seeing a lot of net new customers being acquired directly into the vertical itself. It's supporting the investment hypotheses of existing and new customer acquisition channels.
To answer the second part of your question, yes, from a shipping point of view, okay, shipping supplies, when you utilize dry ice or cold chain, yes, you have a little bit of a higher burden on the shipping supplies cost. At the same time, we are very good at building baskets with consumers and being able to drive repeat purchase using our Autoship program that allows us to plan better, forecast better, and control all inputs that drive operational efficiency in a much more efficient manner. On the whole, at scale, we expect this business to be contribution profit positive and accretive to the base business.
Gotcha. Okay. That's helpful. Thank you for the time.
Our next question comes from Justin Kleber with Baird.
Thanks, everyone. Good afternoon. Just wanted to follow up on the active customer ad questions. Can you give us a sense how those gross customer ads flowed across the quarters in 2020? Were they meaningfully different than the net ads that you reported? Just trying to understand if you've already cycled over the peak period of gross ads and how that might influence the pace of net ads as we look to the back half of this year.
Hey, Justin, it's Mario. The gross adds last year were even throughout the year. Almost the same number of gross adds in Q1 versus Q4, Q3, Q2. You won't find any discernible pattern there.
Okay. Thanks for that. Just lastly on as it relates to your outlook, what are you guys assuming from a promotional perspective in your guidance? Are you embedding a gradual return to a more normalized promo environment, particularly as we head into 4Q and the holidays?
This is actually directly correlated to the way supply chain and out-of-stock issues and overall freight conditions improve. So far, we are continuing to assume a stable and relatively muted promotional environment as we move into the back half of the year.
Okay. If I could just sneak one more in. Just wanted to ask about new pet parents and the maturation of their spending, particularly how it evolved in year 2 as you cycle some of those initial purchases associated with the new pet, picking things like a crate or a cat tree. If you look at spending on an annualized basis, do those new pet parents, do they grow in year 2 in terms of overall spend, or do you see them take a bit of a step back?
No. Whether on a customer basis, per customer basis, or on a cohort basis, revenue retention improves year-over-year. Unlike a traditional retailer where revenue dips from year 1 into year 2, we see a steady, predictable increase from year 1 into year 2. We provided the shapes back in the S-1 document in 2019. When you look at it, for 8 years of cohorts, very predictable. The first year is at $150-$200. The second year jumps to $350. With Mario's recent comments today, we're actually seeing consumer spend higher earlier. No, we don't see a compression. If you're buying full baskets for us, yes. Generally, hard goods purchases are discretionary, and the buying cycle is a little bit longer. On a consumables basis, we're able to forecast repeat purchase and frequency pretty accurately.
On a net basis, the spend actually increases from year one into year two.
Yep. Okay. Thank you, guys. Appreciate the color.
Sure.
Our final question today comes from Steven Forbes with Guggenheim.
Good evening. Sumit, I wanted to follow up on Chewy Health. You mentioned in the release that veterinarians can now earn revenue when a customer places an order. I was curious if you could provide any context around how this revenue share compares to other options the vet may have today, and/or whether you think the improved value proposition has now neutralized the fulfillment preference, enabling the customer to truly drive the decision process as we think about the potential for market share gains into the future?
Our offering is very competitive, and we believe that it should allow the veterinarians to be. The vets control a part of that equation in the way that they price products with us. We might charge a small fulfillment fee, and that fulfillment fee is lower than what we currently see in the marketplace. From that standpoint, we believe this should be accretive, and the vet should be very happy with the overall equation when they engage with Chewy and our customers in a holistic manner. Then, I'm sorry, I did not follow the second part of your question, so would you please repeat that for me?
I think you answered. I was just curious whether you think the offering, right, that you're putting forth here really neutralizes the fulfillment preference among the vets, enabling your customers, right, to really drive the decision process.
Practice Hub, it's completely different than any other product or service in the marketplace currently. First, the service sits on chewy.com with 20 million active customers who now have immediate access to buy from their vet. Secondly, Chewy owns the entire customer experience. We ship for free over $49. We don't charge them for life-saving items like insulin, which currently are being charged. You could expect to pay +$30 on a single order with services that are available out there right now. We ship fast. It gets to you in one to two days, relative to the current delivery experience is somewhere between four and six days, the way that we've benchmarked it.
Then Chewy customer care team is accessible to you, which is available 24/7, on top of us delivering tremendous value proposition on a P&L basis as well as customer base. When you say neutralized, I actually believe that this is a really compelling, superior product, and an industry-defining, industry-disruptive product that we're bringing to life here. We're very proud of it.
Super helpful. Just a quick one for Mario, if I may. Just regarding the software enhancements that you discussed in the prepared remarks, any timeframe behind the recognition of the benefits that were mentioned? Are there any incremental scaling benefits that we should be considering?
For the software, H1 is fully deployed and fully ramped. There's no specific timeline that I can provide you on that. It's something that we've begun to roll out through the network. Your second part of the question was about additional scaling benefits. Continued mix of sales, shifting into the higher-margin verticals that we've talked about. The simple math of increasing our repeat order base, because repeat orders tend to be more profitable than first order. Scale alone, which should provide us additional benefits over time in the supply chain efficiencies. There's a few tailwinds there.
What we find very encouraging, and is the fact that we continue to improve customer engagement and develop our customers and combined with the benefits of our scale, we continue to deliver incremental gross margin. Which is tremendous because the work that we're doing there is structural, and customer-centric, and P&L-centric. At the same time, when you flow this down, presently, there are macro environments that are hopefully temporary in nature, that are holding back kind of the flow-through that goes from the gross margin all the way down to the EBITDA line. Even with the current constraints, we've delivered roughly $300 million on a stack basis over the last two years into the P&L. On a year-over-year basis, we will deliver 2x the EBITDA this year relative to last year.
The scale and the efficiency, and the work that we're doing with customers, we believe we're on the right path and the strategy's intact.
Thank you.
This concludes our question and answer session. I'd like to turn the call back over to Sumit Singh for any closing remarks.
Thank you very much. Stay safe. Have a great evening.