Payment aggregators such as Stripe, Square, and PayPal provide instant onboarding and simplified pricing, but their standardized flat-rate models (for example, 2.9 percent plus 0.30 dollars for online card payments) become disproportionately expensive as merchants scale. Aggregators usually do not pass through B2B interchange incentives (including Level 2 and Level 3 qualification) and have introduced more ancillary fees in 2024 and 2025. For companies processing several million annually, these blended rates materially inflate acceptance costs, making it essential to evaluate whether the startup-friendly stack still aligns with financial maturity.
Why Frictionless Payments Can Become Frictionless Margin Erosion
Aggregators are the reason modern commerce is fast. You paste a snippet of code, skip underwriting, and begin collecting revenue immediately. For early-stage companies, this is a strategic advantage.
As businesses grow into seven and eight figure volumes, frictionless payments can become frictionless margin erosion.
Throughout 2024 and 2025, Stripe, Square, and PayPal expanded their product ecosystems. With that expansion came added fees tied to disputes, software modules, and new network rule changes.
For mid-market CFOs, the key question becomes whether the aggregator is supporting scale or taxing it.
The Flat-Rate Illusion: 2.9 Percent Is Not a Market Rate
Aggregators built their brand on predictable pricing such as 2.9 percent plus 0.30 dollars.
Stripe PricingIn B2B environments, this rate is almost always higher than the cost of Interchange Plus.
Underlying economics:
- Regulated debit interchange is roughly 0.21 dollars plus 0.05 percent under Durbin Amendment regulations
- B2B transactions can qualify for significantly lower interchange when Level 2 or Level 3 data is provided
Paying 2.9 percent for a transaction that may cost an aggregator less than half that amount creates meaningful overpayment. On 10 million dollars in volume, even a 0.80 to 1.20 percent delta produces six-figure excess cost.
2025 Aggregator Changes: The Feature Tax Era
1. Updated Dispute Fee Structures
Stripe Disputes DocumentationAggregators publicly list dispute fees for many regions. They have also expanded paid chargeback support via fraud tools. These dispute fees generally are not refundable if the merchant wins unless subscribed to specific tiers. This increases the cost of managing disputes and friendly fraud.
2. Revenue Recognition as a Paid Product
As of 2024 and 2025, revenue recognition is offered as a paid add-on by major aggregators. This means merchants pay for premium flat-rate processing plus additional SaaS layers.
The Data Black Hole: Why Aggregators Block B2B Optimization
To qualify for B2B interchange incentives, merchants must send detailed invoice-style data such as tax amounts and freight.
Aggregators generally do not allow:
- Merchant-specific MCC configuration
- Merchant-specific qualification logic
- Gateway-level data enrichment
- Level 2 or Level 3 field submission
- B2B data controls at the merchant ID level
Reason: aggregators pool thousands of businesses into an aggregated master merchant account.
Result: most corporate and purchasing card transactions settle at higher-cost categories. This becomes even more material under Visa's Commercial Enhanced Data Program (CEDP).
Visa CEDP OverviewThe Control Problem: Holds, Freezes, and Risk Algorithms
Because aggregators provide instant onboarding, their underwriting happens after transactions begin, not before.
Mid-market merchants often experience:
- Funding holds after volume spikes
- Rolling reserves with little notice
- Delayed payouts during account reviews
- Restrictions based on dispute ratios
- Holds triggered by card brand monitoring patterns
With a dedicated merchant account, underwriting occurs before volume flows and funding limits are set up front. Sudden freezes are materially less common.
For businesses with payroll or time-sensitive supplier payments, funding delays create liquidity exposure.
A Hybrid Strategy That Works
Aggregators are excellent platforms for the right stage of business. The issue arises when simplicity is mistaken for efficiency.
Mid-market analyses consistently show:
- Aggregators are often not cost-efficient at scale
- Flat rates bypass B2B incentives
- Limited data fields cause unnecessary downgrades
- Ancillary SaaS layers compound the true cost
Most mid-market firms keep their aggregator for:
- Self-serve checkout
- Developer-friendly workflows
- Low-ticket online payments
And migrate:
- Invoiced payments
- B2B transactions
- High-ticket sales
- Enterprise contracts
To dedicated merchant accounts optimized for Level 2 and Level 3 qualification and compliant with CEDP expectations.
This preserves operational simplicity while eliminating the growth tax.
Key Takeaways for Finance Leaders
Aggregators solved the problem of payment complexity. As companies scale, this convenience becomes expensive.
A flat 2.9 percent rate on B2B volume is not a neutral convenience. It is a structural premium that intensifies with growth.
With more aggregator fees, SaaS upcharges, and risk algorithms emerging in 2025, CFOs must reassess whether aggregator convenience still aligns with mid-market financial discipline.
The real question is no longer whether Stripe or Square is good. It is whether they are still the right financial architecture for your current stage of scale.
