Payment Processors Beyond Visa and Mastercard: Adyen, Stripe, and Block

Beyond the Rails: Why the Acquiring Layer Matters

When most investors think “payments,” they think Visa and Mastercard. And that instinct is not wrong. The network duopoly runs what are arguably two of the five best business models in public equities — asset-light, toll-booth economics with 60%+ operating margins and no credit risk. We covered this thesis in detail in our analysis of the Visa and Mastercard payments duopoly.

But the payments value chain does not end at the rails. Between the card networks and the merchant sits a layer of acquiring, processing, and software companies that actually touch the merchant relationship. This is where Adyen builds unified commerce platforms for enterprise retailers. Where Block bundles point-of-sale hardware with working capital loans and payroll. Where Stripe provides the API infrastructure that every internet company builds its checkout on. Where Toast gives restaurants an all-in-one operating system from online ordering to kitchen display to staff scheduling.

The economics at this layer are fundamentally different from V/MA. Take rates are higher (typically 2.5–3.0% of transaction value versus V/MA's 20–25 basis points) but so are costs, because acquirers pass through interchange to the networks and issuing banks. Net revenue margins after interchange range from 20–60 basis points depending on merchant size, mix, and geography. Margins are lower — EBITDA margins of 20–50% versus V/MA's 60%+ operating margins. But revenue growth rates are structurally higher, because these companies are taking share from legacy acquirers, expanding into adjacent software and financial services, and riding the same underlying secular shift from cash to digital.

Adyen: Unified Commerce for the Enterprise

The Single-Platform Advantage

Adyen is the rare payments company that genuinely built something architecturally different. Where competitors like Worldpay and Global Payments assembled their tech stacks through dozens of acquisitions — stitching together separate systems for e-commerce, in-store, mobile, and fraud management — Adyen built a single platform from scratch that handles authorization, settlement, risk management, and reporting across every channel and every geography. One codebase. One data lake. One reconciliation engine.

For an enterprise merchant like LVMH, McDonald's, Spotify, or eBay, this means seeing every customer interaction — online browse, in-store purchase, mobile app return — through a single pane of glass. The data advantage is enormous. Adyen can identify that the customer who abandoned a cart online just walked into a physical store, enabling the kind of cross-channel personalization that fragmented payment stacks simply cannot support. This is why Adyen wins enterprise deals despite often charging a modest premium to legacy acquirers.

Adyen processed €1.29 trillion in volume in 2025, generating €1.84 billion in net revenue (after deducting interchange passed through to networks and issuers). The company reported an EBITDA margin of 53%, roughly flat year-over-year, with free cash flow of €810 million. These are exceptional unit economics by any measure. Employee count reached approximately 4,500, giving Adyen revenue per employee well above €400,000 — a reflection of the operating leverage inherent in a single-platform model that does not need armies of integration engineers maintaining separate systems.

The Deceleration Debate

Here is where it gets complicated. Adyen's net revenue grew at 60%+ annually from 2019 through 2022, fueled by COVID-accelerated e-commerce adoption and rapid enterprise wins. Growth then decelerated to roughly 23–27% in 2024–2025, and the market repriced the stock accordingly. Shares dropped from an all-time high of €2,690 in November 2021 to below €700 in the 2023 selloff before recovering to approximately €1,400–1,600 in early 2026.

Two forces are driving the deceleration. First, take rate compression. As Adyen wins larger enterprise merchants who process higher volumes, the blended take rate declines because large merchants negotiate lower per-transaction fees. Adyen's take rate fell from roughly 15.4 basis points in 2022 to approximately 12.8 basis points in 2025. This is structural and expected — it happens to every acquirer that moves upmarket — but it means volume growth needs to significantly exceed net revenue growth. Second, competitive intensity in North America has increased, with Stripe and Braintree (PayPal) aggressively pursuing the same enterprise merchants Adyen is targeting. Adyen's North American revenue growth lagged its EMEA and APAC segments in 2024–2025, suggesting the competitive landscape is tighter in the U.S. than in Europe where Adyen has a stronger incumbent advantage.

Block: The Two-Sided Payments Flywheel

Seller Ecosystem — More Than a Card Reader

Block's seller ecosystem started as a white card reader that let small businesses accept card payments. It has since evolved into an integrated commerce platform encompassing point-of-sale software, online stores, invoicing, inventory management, team management (payroll and scheduling), banking (Square Checking and Savings), and working capital loans (Square Loans). The seller ecosystem generated approximately $7.4 billion in revenue and $3.2 billion in gross profit in 2025, with gross profit growing 14–16% year-over-year.

The strategic pivot under CEO Jack Dorsey (now executive chairman, with Amrita Ahuja as CFO) has been moving upmarket from micro-merchants to mid-market and larger sellers. Square's average seller GPV (gross payment volume) has increased meaningfully as the platform added features that mid-market restaurants, retailers, and service businesses actually need — multi-location management, advanced reporting, loyalty programs, and hardware options beyond the original card reader. This upmarket shift improves unit economics (larger merchants generate more software revenue per dollar of GPV) but puts Block in more direct competition with Toast in restaurants, Shopify in e-commerce, and Lightspeed in retail.

Cash App — 57 Million Monthly Active Users and Counting

Cash App is the consumer side of Block's flywheel. With 57 million monthly active users as of Q4 2025, Cash App has become a mainstream consumer financial app offering peer-to-peer transfers, direct deposit, a debit card (Cash Card), stock and Bitcoin investing, savings accounts, and tax filing (through the Cash App Taxes acquisition). Cash App generated approximately $4.4 billion in gross profit in 2025 — more than the seller ecosystem — driven by Cash App Card adoption (spending per active user growing 10–15% annually), direct deposit inflows, and subscription services like Cash App Borrow.

The flywheel thesis is straightforward: when a consumer pays a Block merchant using Cash App, both sides of the platform benefit — the merchant stays in the seller ecosystem and the consumer stays in Cash App. Block has started to close this loop more aggressively, with Cash App offering discovery features that surface nearby Square merchants and Cash App Pay as a checkout option at Square sellers. The execution challenge is that Cash App's user base skews younger and lower-income than Venmo or traditional banking apps, which limits monetization per user and creates credit quality concerns for lending products like Cash App Borrow.

The Bitcoin Revenue Distortion

Block reported approximately $12.1 billion in Bitcoin revenue in 2025, representing roughly 44% of consolidated revenue. Strip away the headlines and the picture is far less dramatic. Bitcoin gross profit was approximately $300–350 million, implying a gross margin of 2–3%. Block is essentially acting as a Bitcoin brokerage for Cash App users, buying Bitcoin at market price and selling it at a small markup. It is a low-margin pass-through business that inflates the top line without contributing meaningful profitability.

This is why most serious analysts value Block on gross profit rather than revenue. On a gross profit basis, Block generated approximately $8.6 billion in 2025, growing 17–19% year-over-year. The company's adjusted EBITDA reached roughly $2.1 billion, implying a gross-profit-to-EBITDA conversion of approximately 24%. Management has guided for this ratio to improve to 30%+ by 2027 through operating leverage and cost discipline. Whether they hit that target will determine whether Block trades as a growth story (30–35x gross profit) or a value trap (20x gross profit with margin stagnation).

PayPal: Turnaround or Structural Decline?

PayPal under Alex Chriss is a different company than PayPal under Dan Schulman. Schulman's strategy was growth at all costs — expanding total payment volume by discounting Braintree's unbranded checkout to win enterprise merchants, even as it cannibalized PayPal's higher-margin branded checkout button. The result was impressive TPV growth ($1.68 trillion in 2025) but deteriorating transaction margins that punished the stock from $310 in July 2021 to below $60 in late 2023.

Chriss has reoriented the strategy around transaction margin dollars rather than total payment volume. This means accepting slower TPV growth if it comes with better margin mix — defending branded checkout (where PayPal earns 40–50+ basis points of net take rate versus 10–15 basis points on unbranded Braintree volume), selectively repricing Braintree contracts to improve profitability, and launching Fastlane (a one-click guest checkout product that accelerates conversions without requiring a PayPal account). Fastlane is strategically important because it directly addresses the friction problem that has driven merchants toward Shop Pay (Shopify) and Apple Pay.

The financial profile reflects early turnaround progress. Transaction margin dollars grew 5–7% year-over-year in the back half of 2025 after being flat-to-declining for the prior two years. Non-GAAP EPS grew roughly 10–12%, aided by aggressive buybacks ($5+ billion annually). Free cash flow of approximately $6.5 billion on $31.5 billion in revenue gives PayPal a 20%+ FCF margin — healthy by any standard. At 15–17x NTM earnings, the stock prices in near-zero revenue growth. Any sustained acceleration in branded checkout or Fastlane adoption would create meaningful upside from multiple re-rating alone.

Stripe: The Private Market Juggernaut

Stripe is the most consequential payments company that public market investors cannot buy — yet. Founded by Patrick and John Collison in 2010, Stripe has become the default payment infrastructure for internet businesses, processing over $1 trillion in annual payment volume across millions of businesses in 46+ countries. Its last reported private valuation was approximately $91.5 billion following a 2025 secondary share sale, making it the most valuable private fintech company in the world.

What makes Stripe different is not just payments — it is the platform that sits on top. Stripe Billing handles subscription management and invoicing. Stripe Connect enables marketplaces and platforms to onboard sellers and manage payouts. Stripe Treasury and Stripe Issuing allow software platforms to embed banking accounts and debit cards within their own products. Stripe Atlas helps startups incorporate a company. Stripe Tax automates sales tax compliance. Stripe Revenue Recognition handles accrual accounting for subscription businesses. Taken together, this product suite represents a full financial operating system for internet-native businesses — and each additional product a merchant adopts deepens the switching cost exponentially.

Stripe's revenue is estimated at $20–25 billion annually (the company does not publicly disclose full financials), with a net revenue take rate after interchange of approximately 40–50 basis points. The company confirmed profitability in 2024 and is believed to be generating meaningful free cash flow. The co-founders have repeatedly signaled there is no rush to IPO, but market participants broadly expect a listing in the 2026–2028 window. When it happens, it will likely be the largest fintech IPO in history and will create a public market comp that forces re-rating across the entire payments acquiring space — particularly for PayPal and Global Payments, which will face more direct valuation scrutiny against Stripe's growth and margin profile.

Toast: Vertical SaaS Meets Payments in Restaurants

Toast is the clearest example of the vertical software-plus-payments playbook. Rather than trying to be everything to everyone like Block or PayPal, Toast focuses exclusively on restaurants — a $900 billion U.S. industry with roughly 860,000 restaurant locations. Toast's all-in-one platform includes point-of-sale, kitchen display systems, online ordering, delivery management, payroll, team scheduling, marketing and loyalty, and of course payment processing.

The financial trajectory is compelling. Toast's recurring gross profit stream (SaaS subscription and fintech) grew 35%+ year-over-year in 2025, with total locations on the platform reaching approximately 127,000 — roughly 15% penetration of the U.S. restaurant market. The company turned adjusted EBITDA positive in 2024 and expanded margins through 2025, reaching approximately 4–5% EBITDA margin on $4.4 billion in annual revenue. The path to 20%+ EBITDA margins by 2028 is credible given operating leverage on the SaaS line and the high incremental margins of fintech products layered onto existing locations.

The risk is concentration. Toast is a one-vertical company. If the U.S. restaurant industry experiences a downturn — rising labor costs, food inflation, or a consumer spending pullback — Toast's entire revenue base is exposed. The company has started expanding into adjacent verticals (food and beverage retail, hotels) but these are early and unproven. At current valuations of 4–5x NTM revenue, Toast needs to either sustain 25%+ revenue growth and hit its margin targets, or successfully diversify beyond restaurants to justify its multiple. For a deeper look at vertical SaaS investment frameworks, see our analysis of industry-specific software stocks.

Payment Acquirer Comparison: Key Metrics at a Glance

The table reveals a critical nuance: these companies compete in overlapping but distinct markets. Adyen targets enterprise unified commerce, Block serves SMBs and consumers, PayPal owns branded online checkout, Stripe dominates developer-led internet businesses, and Toast owns restaurants. Direct competition exists at the margins — Adyen and Stripe both compete for large platform marketplaces, Block and Toast both target food and beverage merchants — but the core TAMs are different enough that multiple winners can coexist. The framework for understanding these dynamics mirrors how investors analyze competitive moats across industries.

The Bear Case: Margin Compression from Both Directions

Visa and Mastercard Pricing Power Squeezes from Above

Acquirers exist in the shadow of V/MA's pricing power. When Visa raises assessment fees or Mastercard increases network access charges — as both have done regularly over the past decade — acquirers face an uncomfortable choice: absorb the increase (compressing their margins) or pass it through to merchants (risking competitive displacement). Large enterprise merchants with negotiating leverage increasingly demand that acquirers absorb network fee increases, creating a structural headwind for acquirer margins that is largely invisible in headline revenue growth.

The Durbin Amendment caps debit interchange for large banks, but credit card interchange and network assessment fees remain unregulated in the U.S. The Credit Card Competition Act, which would require at least two network options on every credit card (breaking V/MA's exclusive issuer agreements), has been introduced in Congress multiple times but never passed. If it eventually does, it could disrupt the current fee structure in ways that ripple through the entire acquiring chain. For now, V/MA's ability to raise prices by 3–5% annually without losing volume is the single biggest structural risk to acquirer economics.

Fintech Competition Compresses from Below

At the same time, competition among acquirers themselves is intensifying. Stripe's transparent, developer-friendly pricing has set a market expectation for simplicity and fairness that legacy players struggle to match. New entrants like Checkout.com, Mollie, and dLocal are competing aggressively on price in specific geographies and verticals. Embedded payments — where vertical software companies like Mindbody, ServiceTitan, and Procore build payment processing directly into their platforms — is pulling payments revenue away from standalone acquirers and into software companies that view payments as a feature rather than a product.

The worst-case scenario for acquirers is a margin squeeze from both directions simultaneously: V/MA raising network fees from above while competitive pressure caps merchant pricing from below. In this scenario, only acquirers with genuine software differentiation and high switching costs — Adyen's unified commerce platform, Stripe's developer ecosystem, Toast's restaurant operating system — can maintain pricing power. Commoditized acquirers that compete primarily on price (legacy players like Worldpay, and arguably PayPal's Braintree) would face sustained margin compression.

Portfolio Positioning: How to Play the Acquiring Layer

For investors building exposure to the payments acquiring layer, the key decision framework comes down to growth versus value, and platform versus product. Adyen offers the highest-quality business model (53% EBITDA margin, unified architecture, enterprise client base) but also the highest valuation at roughly 55x NTM earnings — pricing in continued 20%+ net revenue growth that is not guaranteed. Block offers a unique two-sided ecosystem and the most undervalued gross profit stream (roughly 5x EV/GP), but carries execution risk around margin expansion and Bitcoin-related volatility. PayPal is the deepest value play at 15–17x earnings, with the turnaround optionality that Chriss's strategy provides, but also the highest risk of structural decline if Braintree continues losing share.

Toast is the purest vertical software play, offering the highest revenue growth with the clearest path to margin expansion, but with concentration risk that makes position sizing important. Stripe, when it eventually comes public, will be the most hotly debated IPO allocation in fintech history. Understanding these companies' relative positioning today — before Stripe's IPO resets the valuation framework for the entire sector — is essential for investors who want to be ahead of the curve rather than reacting to it. The broader fintech investment landscape, including neobanks and lending platforms, is covered in our analysis of fintech stocks in 2026.

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