The numbers do not lie. Affiliate marketing has quietly become one of the most powerful growth levers in the SaaS industry, and the data coming out of 2025 into 2026 makes that clearer than ever before. While many businesses still treat affiliate programs as a secondary revenue channel, top-performing SaaS companies are generating 20 to 30 percent of their new customer acquisitions through structured partner networks.

But growth rarely happens by accident. Understanding what separates thriving affiliate programs from stagnant ones requires a close look at the metrics, the trends, and the strategic decisions driving real results.

In this analysis, we break down the latest data shaping affiliate marketing in the SaaS space. You will discover which commission structures are converting at the highest rates, how customer lifetime value is influencing partner recruitment strategies, and what the most successful programs are doing differently in 2026. Whether you are managing an existing affiliate program or building one from the ground up, the insights here will give you a sharper, evidence-based framework for making smarter decisions.

The State of Affiliate Marketing in 2026

Affiliate marketing has quietly become one of the most structurally significant channels in digital performance marketing, and the 2026 numbers confirm what many growth-focused teams already suspected: this is no longer a supplemental tactic. According to Forrester's 2026 affiliate marketing data, global affiliate channel spend has reached $19.4 billion in 2026, up from $17.1 billion the prior year. Broader definitions of the market, including influencer partnerships and adjacent program types, push that figure closer to $27.8 billion globally, with projections pointing toward $48 billion by 2027 at an 18.6% CAGR through 2032. That growth trajectory places affiliate marketing among the fastest-scaling segments in the entire digital marketing stack, outpacing many legacy acquisition channels on both investment volume and return efficiency.

The channel's rise in stature is equally notable. Affiliate marketing now ranks as the third-largest performance channel globally, sitting behind only paid search and paid social in terms of advertiser spend and adoption. For SaaS companies evaluating where to concentrate acquisition budget, that ranking matters: affiliate has achieved the kind of institutional legitimacy that attracts serious publisher inventory, high-intent audiences, and increasingly sophisticated infrastructure. More than 80 to 83% of brands now operate affiliate programs, a figure that signals a definitive shift from niche growth hack to mainstream revenue infrastructure. Critically, 74% of brands report generating between 11 and 30% of their total revenue through affiliate channels, according to industry benchmarks compiled for 2026. This is not marginal contribution; it is a primary revenue lever for a large portion of the market.

In the United States specifically, affiliate spend is estimated at approximately $13.2 billion in 2026, with domestic investment projected to grow 65% between 2023 and 2028. That sustained growth reflects confident, multi-year commitment from brands across verticals, including SaaS, fintech, health, and e-commerce.

From a capital efficiency standpoint, affiliate remains exceptionally compelling. ROI benchmarks range from $6.50 to $15 for every $1 spent, with average reported returns clustering around $12 per dollar, per Rakuten's published data. For SaaS companies operating under unit economics pressure, that range is difficult to ignore. Unlike paid search, where cost-per-click inflation steadily erodes margin, affiliate spend is performance-bound by design: you pay when outcomes are delivered. SaaS-specific commission structures reinforce this advantage further, with median recurring commissions averaging 22.5% of first-year revenue compared to just 8.4% for e-commerce, making SaaS affiliate programs significantly more attractive to quality publishers and creators who actively choose where to direct their promotional efforts.

Why SaaS Is the High-Commission Outlier in Affiliate Marketing

The commission rate gap between SaaS and every other major affiliate vertical is not a market inefficiency waiting to be corrected. It is a structural feature of the business model. SaaS products carry near-zero marginal fulfillment cost: there is no inventory, no warehousing, no returns processing, and no COGS that scales linearly with each new customer. This cost structure allows SaaS companies to offer affiliate commissions that would be economically impossible for physical goods sellers. The data confirms this clearly: SaaS recurring commissions average 22.5% of first-year revenue, compared to just 8.4% for e-commerce programs, making SaaS affiliate programs nearly three times more lucrative on a commission rate basis alone. Travel sits even lower at approximately 4.2%, and finance lead-generation programs typically pay a flat bounty per lead rather than a revenue percentage. For affiliates doing the math on where to allocate their content and distribution capacity, the SaaS vertical wins on unit economics before any other variable is considered.

The income figures that flow from those commission rates are high enough to attract an entirely different category of affiliate partner. Affiliate managers promoting SaaS products earn commissions ranging from 20% to 70%, and software affiliate marketers average $5,967 per month in earnings, a threshold that separates professional distribution partners from casual link-droppers. When an affiliate program can credibly offer full-time income to a niche content creator, technical blogger, or YouTube educator, it attracts partners who invest in long-form tutorials, comparison content, and SEO-optimized reviews rather than banner placements. That shift in affiliate quality directly improves traffic intent and conversion rates across the program, creating a compounding quality dynamic that purely volume-based recruitment cannot replicate.

Beyond the commission mechanics, SaaS is explicitly identified in current affiliate marketing benchmark data as one of the top growth verticals globally, alongside finance and health. The recurring revenue model at the core of SaaS also creates an incentive alignment that e-commerce affiliate structures cannot replicate. When commissions are tied to ongoing subscription revenue rather than a one-time transaction, affiliates become economically invested in customer retention. An affiliate who refers a customer that churns in month two stops earning on that referral. This means rational affiliates in a recurring commission program will naturally optimize toward qualified, retention-prone customers rather than volume conversions with weak fit. That alignment is structurally valuable: the affiliate's incentive and the founder's growth objective point in the same direction without requiring contractual enforcement.

For early-stage SaaS founders and builders shipping vibe-coded apps, this structural advantage translates into a capital efficiency argument that becomes especially compelling before paid acquisition channels are fully built out. Affiliate commission is only paid on closed, retained revenue, making it a variable cost rather than a fixed budget line. At the pre-scale stage, when cost-per-acquisition from paid search or paid social can be punishing relative to early LTV, an affiliate program converts distribution into a performance obligation rather than a cash burn. Research across SaaS affiliate programs consistently shows that launching affiliate infrastructure early, even with a small number of well-chosen partners, captures compounding distribution leverage that becomes progressively harder to build once a product is competing in a crowded paid acquisition market. The founders who treat affiliate as a day-one growth lever, rather than a later-stage optimization, are the ones who benefit most from its variable cost structure.

Five Trends Reshaping Affiliate Marketing Right Now

The structural forces reshaping affiliate marketing in 2026 are not incremental adjustments. They represent category-level disruptions that are changing how programs are built, measured, and compensated.

Post-ITP 2.3 and Apple ATT have effectively ended the 30-day cookie as a default attribution mechanism. AM Navigator's 2026 program survey confirms that 38% of affiliate programs now operate on 7-day or shorter attribution windows, while only 21% retain 60-day windows. That compression is not neutral. Affiliates promoting considered purchases, such as SaaS subscriptions, B2B tools, or high-ticket services, operate in categories where the buyer journey routinely exceeds seven days. A shortened window structurally underreports their contribution. The practical response is migration to server-side and first-party tracking infrastructure, and programs that have made this move report 18 to 24% higher attributed conversions than those still dependent on third-party cookies. That delta represents real revenue being misattributed or lost entirely.

AI Has Moved from Experiment to Infrastructure

Seventy-eight percent of affiliate marketers now use AI tools for content creation, campaign optimization, and predictive analytics, according to 2026 data from Affiverse cited by Avangate Network. The performance implications are compounding quickly. AI-enabled affiliates can test headline variations at scale, personalize landing pages by traffic source, and model offer conversion rates before committing media spend. On the network side, AI-driven fraud detection reduced invalid affiliate traffic from 11.2% of clicks in 2024 to 7.7% in 2026, a 31% reduction year-over-year. The gap between data-sophisticated affiliates and manual operators is widening every quarter, which places pressure on brands to provide robust real-time reporting if they want to attract and retain top-tier partners. For a deeper look at the affiliate marketing trends redefining performance in 2026, the structural AI shift is increasingly non-negotiable.

Creator Affiliates Are Outperforming Traditional Display

Impact's 2026 Partnership Benchmark Report documents that creators with 10,000 to 100,000 followers generate 3.7x more attributable revenue per follower than traditional display affiliates on a comparable audience basis. The performance gap widens further in beauty, fashion, and gaming verticals. Shoppable video placements across TikTok Shop, YouTube Shopping, and Instagram Shopping grew 71% year-over-year and are projected to overtake banner-display affiliate revenue entirely by Q3 2027. The mechanism is straightforward: creator content generates purchase intent in context, rather than interrupting consumption. Brands that have not yet restructured their affiliate mix to include micro and mid-tier creator partnerships are leaving a measurable revenue advantage unaddressed.

Commerce Content Is Structurally Dominant

Editorial and review-driven affiliate content grew 34% year-over-year and now accounts for approximately 28% of total affiliate revenue. Two forces are driving this simultaneously: AI-assisted publishing velocity allows editorial teams to produce comparison and review content faster than traditional production cycles permitted, and consumer trust in independent editorial continues to outperform trust in brand advertising. The format is structurally durable because it aligns with how buyers actually research purchases. Quality differentiation and genuine expertise signals are increasingly important as AI-generated review volume rises across search results.

Incrementality Testing Is Changing Commission Economics

Perhaps the most consequential shift for program economics is the growing adoption of incrementality testing. Programs running these analyses consistently find that 18 to 24% of attributed affiliate conversions would have occurred organically without any affiliate touchpoint. Brands are now using this causal attribution data to renegotiate commission structures, moving away from last-click models toward payout frameworks that reflect actual incremental lift. As the affiliate marketing forecast through 2026 and beyond makes clear, the programs that survive and scale are those built on measurement integrity rather than attribution assumptions.

The Attribution Gap Most Affiliate Programs Are Ignoring

The measurement infrastructure beneath most affiliate programs has not kept pace with the privacy changes that have fundamentally altered how browsers handle cross-site data. Programs still relying on third-party cookie tracking are operating with a systematic blind spot, and the scale of that blind spot is now quantifiable. Research consistently shows that programs using server-side tracking report 18 to 24% higher attributed conversions than those dependent solely on third-party cookies. For a SaaS program paying out $500,000 annually in affiliate commissions, that gap represents roughly $100,000 to $120,000 in affiliate-driven MRR that program managers cannot see, cannot credit, and cannot use to make scaling decisions. The revenue is being generated; it is simply invisible to the attribution layer.

The problem is structurally worse for SaaS than for any other affiliate vertical, and that is not an accident of circumstance. It follows directly from how SaaS products convert. A typical affiliate-driven SaaS acquisition unfolds across a sequence of events: an affiliate click in session one, a free trial signup in session two, a series of activation milestones across sessions three through five, a paid conversion potentially two to four weeks later, and a plan upgrade months after that. Cookie-based attribution was architected for single-session e-commerce transactions. It breaks at every meaningful step in the SaaS funnel. Apple's ITP 2.3 caps first-party cookies set via JavaScript to seven days in Safari. Firefox applies similar restrictions. With 38% of affiliate programs now using attribution windows of seven days or shorter, the paid conversion event, which is where SaaS affiliate commissions are actually triggered, falls outside the trackable window for a substantial share of traffic.

Google's decision to move away from full third-party cookie deprecation in Chrome, opting instead for a user-consent prompt model, has led some program managers to delay infrastructure changes. That reasoning does not hold up under scrutiny. Safari and Firefox have already made third-party cookies functionally unreliable for multi-session attribution, and real-world opt-in rates for cookie consent prompts trend well below 50% in most markets. Waiting for a Chrome-specific resolution while ignoring the broader browser landscape means accepting a permanent attribution gap for a significant share of affiliate traffic. The cookieless affiliate tracking guide from Stape makes clear that server-to-server tracking has already emerged as the operational standard for programs that need reliable cross-session attribution.

The Infrastructure That Closes the Gap

First-party data models and server-side event tracking resolve the core problem by moving affiliate conversion signals out of the browser and into a controlled, consent-based data environment. Rather than relying on a cookie to persist an affiliate click ID across sessions, server-side implementations pass that identifier through the product's own infrastructure, linking it to downstream events at the database level. As IREV's analysis of affiliate marketing without cookies demonstrates, server-to-server integrations allow affiliate programs to connect a click to a trial start, an activation event, a first charge, an upgrade, and even a churn event, with each step tied back to the originating affiliate source.

For SaaS teams, the specific events that need instrumentation are trial start, activation milestone (the point at which a user completes the core value action), first charge, plan upgrade, and cancellation. Without all five events firing server-side and carrying the affiliate click ID forward, the attribution model collapses precisely where SaaS growth actually occurs: in the conversion from free trial to paid subscription. This is the gap that makes affiliate commission structures unreliable and forces program managers into guesswork when deciding which affiliate partners to invest in.

FunnelKeeper addresses this directly by enabling SaaS teams to build attribution dashboards that connect affiliate traffic sources to the full downstream funnel, including MRR activation, plan upgrades, and churn signals. Rather than reporting on clicks and signups in isolation, program managers can see which affiliates are driving paid conversions, which are driving high-value plan upgrades, and which are generating trial volume that never converts. That level of funnel visibility transforms affiliate program management from an accounting exercise into a genuine growth lever, giving teams the data they need to negotiate commission structures with confidence and scale partnerships based on actual revenue contribution rather than last-click assumptions.

Full-Funnel Affiliate Benchmarks Every SaaS Team Should Know

The benchmarks that follow are not directional indicators. They are operational calibration points that should inform how SaaS teams structure, measure, and invest in affiliate programs at every stage of the funnel.

The 90/10 Concentration Reality

Revenue distribution in affiliate programs follows a power-law curve with little variation across verticals. The top 10% of affiliates generate approximately 90% of total program revenue, which means the long tail of registered partners contributes negligible output while consuming management overhead. For SaaS affiliate managers, this concentration stat reframes the entire program strategy. Recruitment volume matters far less than recruitment precision. Activation workflows, commission tier structures, and reporting visibility should all be engineered around the top decile, not average partner behavior. Programs that optimize for breadth over depth consistently underperform programs that identify their highest-potential partners early and invest disproportionately in their enablement and retention.

Affiliate as a Primary Revenue Line

The framing of affiliate as a supplemental or experimental channel no longer aligns with what the data shows operationally. According to affiliate marketing industry benchmarks, 74% of brands generate between 11% and 30% of total revenue through affiliate channels. A revenue line contributing up to 30% of total company output is not a secondary acquisition experiment; it is a core business function that warrants dedicated funnel measurement infrastructure, executive visibility, and attribution tooling capable of tracking partner-sourced conversions from first click through trial, activation, and paid conversion. SaaS teams that still manage affiliate inside a broader "partnerships" budget line, without distinct funnel reporting, are structurally unable to optimize what they cannot isolate.

Cookie window strategy is one of the most underexamined levers in SaaS affiliate program design. Currently, 38% of programs operate on attribution windows of seven days or fewer, while only 21% maintain 60-day windows. For high-consideration SaaS products where evaluation cycles routinely span two to four weeks, a sub-7-day window does not reflect buyer behavior; it systematically undercounts conversions and misattributes revenue that affiliate partners legitimately influenced. Programs that have shifted to server-side tracking report 18 to 24% higher attributed conversions compared to those relying solely on third-party cookies. The practical implication is direct: mismatched attribution windows are not just a measurement problem, they are a commission accuracy problem that degrades affiliate trust and suppresses partner motivation over time.

Fraud Reduction and Program Quality Gains

AI-powered fraud detection has materially changed the quality composition of affiliate traffic. Invalid traffic across major networks has dropped from 11.2% to 7.7%, a 31% reduction that translates directly into a larger share of affiliate spend reaching genuine acquisition opportunities. Separately, incrementality testing is surfacing another nuance: approximately 18 to 24% of attributed affiliate conversions would have occurred organically without an affiliate touchpoint. These two figures together reshape how SaaS teams should calculate and report program ROI internally, moving from gross attributed revenue to a net incrementality-adjusted contribution model.

The Tooling Investment Signal

The affiliate marketing software market is projected to reach $2.1 billion, with software already commanding 62.5% of total affiliate market infrastructure spend in 2025. As performance partnership analysis confirms, this investment reflects a structural shift away from standalone networks toward integrated platforms capable of handling attribution, partner tiering, funnel reporting, and commission management in a single environment. For SaaS teams, the takeaway is actionable: affiliate programs that rely on network-native reporting alone are operating without the funnel visibility needed to identify which partners drive qualified trial users versus low-intent signups that churn before activation. Integrated attribution platforms close that gap and make the 90/10 concentration dynamic visible at every funnel stage, not just at the final conversion event.

What This Data Means for SaaS Growth Teams in Practice

The benchmarks covered in previous sections are only useful if they translate into operational changes. For SaaS growth teams, the practical implication starts with a fundamental shift in how affiliate tracking is instrumented. Most programs treat the signup event as the terminal conversion, which creates a dangerously incomplete picture. A user who signs up through an affiliate link but never activates a core feature, never completes onboarding, and churns within 30 days represents a cost, not a conversion. Tracking needs to capture trial starts, onboarding completions, feature activations, and paid conversion events as discrete attribution signals. This event-level instrumentation is a logical extension of the server-side tracking infrastructure that leading programs are already migrating toward, and it gives growth teams the data resolution needed to evaluate affiliate quality rather than affiliate volume.

Build Tiers Around the 10/90 Reality

The concentration data carries a direct operational implication: since roughly 10% of affiliates generate approximately 90% of revenue, the highest-return activity in any program is identifying that top tier and treating it differently from the rest of the partner base. This means dedicated reporting views, faster commission payouts, and direct communication channels for top performers. Critically, this tier structure requires real-time affiliate performance dashboards connected to actual MRR data rather than lagging vanity metrics like click volume or raw signup counts. A partner who drives 40 signups but zero paid conversions should not receive the same program investment as one who drives 15 signups with an 80% trial-to-paid rate. Funnel dashboards that surface these distinctions make tier assignments defensible and dynamic rather than arbitrary.

Treat Server-Side Migration as Revenue Recovery

Programs still running on third-party cookie infrastructure are not just accepting a measurement gap; they are leaving attributed revenue unrecorded. The conversion lift associated with server-side or first-party tracking, estimated at 18 to 24% in programs that have completed the migration, represents a concrete revenue recovery opportunity rather than a technical nicety. For any SaaS team where affiliate contributes a meaningful share of new MRR, that percentage range translates directly into commissions that should have been paid out, revenue that should have been credited, and partner relationships that may have been underfunded because the data appeared weaker than it was. Migration is no longer a roadmap item; it is a prerequisite for running a program with accurate ROI data.

Build Incrementality Testing Into Quarterly Reviews

Accurate attribution still does not answer the most important question: would those conversions have happened without the affiliate? Incrementality testing using holdout groups should be a standing component of quarterly program reviews. By routing a statistically defined percentage of eligible traffic to a no-affiliate condition and comparing conversion rates against the affiliate-exposed group, teams can isolate genuine lift from coincidental attribution. This prevents commission overpayment on conversions that were already organic and sharpens the true cost-per-acquisition figure for each partner. The affiliate industry broadly acknowledges that a portion of attributed conversions, sometimes estimated above 18%, would have occurred through direct or organic channels regardless of affiliate involvement.

Start Focused, Then Scale With Evidence

For lean SaaS teams and vibe-coded app builders who are earlier in their affiliate journey, the concentration data supports a deliberately constrained starting point. A focused program of 10 to 20 carefully selected, high-intent affiliates allows growth teams to validate attribution infrastructure, test commission structures, and identify which partner profiles produce users who actually retain before scaling spend. Funnel dashboards become the decision layer here, surfacing which partners are driving users past the activation threshold versus which ones are generating trial starts that stall. Scaling an affiliate program before attribution is solid means scaling both the revenue potential and the measurement errors simultaneously, which is a compounding problem that becomes significantly harder to unwind at volume.

Building the Affiliate Funnel Infrastructure That Actually Scales

Translating the benchmarks and attribution principles covered earlier into actual infrastructure requires moving beyond conceptual frameworks and into the specific architectural decisions that determine whether a SaaS affiliate program scales or stalls. A program built on solid infrastructure compounds over time; one built on shallow tracking collapses under its own data gaps the moment the team tries to optimize beyond top-of-funnel volume.

The Three-Layer Stack SaaS Programs Need

A scalable affiliate program for SaaS requires three interconnected layers working in concert. The tracking layer captures affiliate-sourced events reliably, using server-side tracking or first-party pixels rather than third-party cookies that browser privacy changes have made increasingly unreliable. Programs running server-side tracking report 18 to 24% higher attributed conversions compared to those still dependent on cookie-based methods, which means the tracking layer alone has measurable revenue implications. The attribution layer sits above raw event capture and applies multi-touch models that span the entire trial-to-paid journey, assigning appropriate credit across the free trial signup, onboarding engagement, feature activation, and eventual conversion to a paid plan. The reporting layer connects all of this to the revenue metrics that SaaS unit economics actually depend on: MRR contribution, cohort-level churn rates, and customer LTV broken down by affiliate source. Without all three layers functioning together, growth teams are optimizing against incomplete signals.

What Affiliate Networks Handle (and What They Don't)

Platforms like PartnerStack, Impact, and Rewardful solve real operational problems. They provide recruitment infrastructure, automated commission disbursement, affiliate onboarding workflows, and a centralized view of partner-level click and conversion data. For early-stage SaaS teams, these capabilities remove significant administrative friction and are the right starting point for building a partner ecosystem. However, none of these platforms were built to function as full-funnel attribution systems. They capture the conversion event, but they do not connect that event to what happens downstream in the product: whether the affiliate-sourced user activates key features, whether they convert from trial to paid within a normal window, whether they churn at month three, or whether they expand to a higher tier at month six. That gap is not a platform deficiency; it is simply outside their scope. Closing it requires a separate attribution layer that ingests both affiliate source data and product and revenue events.

Commission Design as a Strategic Alignment Tool

Most early-stage SaaS teams set a flat commission rate and move on, treating structure as an administrative detail rather than a strategic lever. Tiered commissions tied to affiliate-driven customer LTV or retention milestones change the incentive dynamic in a meaningful way. When a partner earns a higher commission rate for customers who remain active past 90 days, or who expand into a higher-tier plan, the partner's promotional strategy naturally aligns with the product's retention goals. This matters because 10% of affiliates typically generate approximately 90% of program revenue, meaning the commission structure disproportionately shapes the behavior of the partners who drive the most impact.

Real-Time Cohort Visibility and Budget Reallocation

Real-time dashboards that surface affiliate contribution by cohort, by partner, and by funnel stage give growth teams the data velocity needed to reallocate budget toward affiliates who drive high-retention customers. Without cohort-level visibility, a program manager cannot distinguish a partner generating high signup volume with 60% three-month churn from one generating half the signups with 15% churn and 120% net revenue retention. FunnelKeeper's attribution and dashboard capabilities are built specifically for this infrastructure stack, giving SaaS growth teams clear visibility into how affiliate-driven users move from first touch through trial activation to paid conversion, without requiring a dedicated data engineering team to instrument and maintain the pipeline. For lean growth teams under pressure to demonstrate channel ROI across the full funnel, that combination of depth and accessibility is where affiliate program infrastructure finally becomes a compounding growth asset rather than a reporting liability.

Affiliate Marketing as a SaaS Growth Lever: Key Takeaways

Affiliate marketing has graduated from a supplementary acquisition tactic to a primary revenue channel for SaaS businesses, and the data confirms that trajectory will continue. With global affiliate spend reaching $19.4 billion in 2026 and a projected CAGR of 18.6% through 2032, the investment case is durable. SaaS teams generating between $6.50 and $15 in return per dollar spent are not outliers; they are operating programs with solid attribution foundations.

The single greatest risk heading into this environment is not competitive pressure but measurement failure. Teams without server-side tracking are systematically miscounting conversions, misidentifying top performers, and misallocating commission budgets. Programs that have addressed this report 18 to 24% higher attributed conversions, a gap wide enough to change program-level investment decisions entirely.

Three infrastructure decisions define whether a program compounds or stagnates: server-side tracking, incrementality testing, and full-funnel dashboards. According to affiliate marketing research from FirstPromoter, roughly 10% of affiliates generate 90% of revenue, which means identifying and retaining those partners accurately is operationally critical. Building attribution clarity before scaling partner count is the highest-leverage move available to any SaaS growth team right now.

Conclusion

The data tells a compelling story. Affiliate marketing is no longer a side channel for SaaS companies; it is a primary growth engine for those willing to build it strategically. The key takeaways are clear: commission structures matter enormously, customer lifetime value should drive every partner recruitment decision, and the gap between high-performing and underperforming programs comes down to intentional design.

Success in 2026 belongs to companies that treat their affiliate partners as true growth collaborators, not just referral sources.

If you are ready to turn these insights into action, start by auditing your current program against the benchmarks outlined here. Identify one area to optimize this quarter, whether that is your commission model, partner onboarding, or tracking infrastructure. Small, data-driven adjustments compound quickly. The companies winning today did not overhaul everything at once. They simply started.

Affiliate Marketing in 2026: What the Data Says About SaaS Growth