The short answer
A processor aggregator (also called a Payment Facilitator, PayFac, or aggregated merchant services provider) is a payments company that has one primary merchant account with the card networks and "sub-merchants" every one of their customers underneath it. When you sign up for Stripe in 10 minutes, you're not getting your own merchant account — you're getting a sub-merchant entry inside Stripe's master MID. Your transactions clear through Stripe's acquirer; your payouts come from Stripe.
Aggregators vs. dedicated merchant accounts
- Aggregator (Stripe, Square, PayPal): Instant signup. Flat-rate pricing. Shared MID. Single underwriting model. Termination is unilateral. No negotiation leverage below $1M+/mo.
- Dedicated merchant account: 1-4 week underwriting. Interchange-plus pricing negotiable. Your own MID + descriptor. Individual underwriting. Termination requires cause (usually). Pricing power at $30k+/mo.
What aggregation gets you
- Onboarding in minutes instead of weeks.
- Flat-rate pricing that's predictable for small volumes.
- Built-in fraud tools, checkout UIs, and developer SDKs.
- No minimum volume commitments.
- Automatic 1099-K reporting.
What it costs you
- Pricing power. Aggregators don't negotiate pricing below the enterprise tier. A $5M/yr operator still pays Stripe 2.9% + $0.30 unless they qualify for custom pricing — usually at $1-2M/yr in volume.
- Unilateral termination. Aggregators reserve the right to offboard merchants at any time, for any reason, with 30 days' notice or less. If you're in a high-risk vertical, your runway is measured in weeks.
- Shared descriptor. On some aggregators, your billing descriptor is derived from the aggregator's name (e.g., "SP* YOURBRAND"). Customer recognition suffers and chargebacks climb.
- Shared fate on risk. Aggregators react to their overall portfolio risk. If high-risk categories spike chargebacks, tolerance across the whole aggregator tightens — including for unrelated merchants.
- Hold and release schedules. Aggregators hold more aggressively than dedicated acquirers. 7-14 day holds on new accounts are common; so are 90-180 day reserves on high-risk categories.
When an aggregator is the right answer
- Low-risk vertical. Apparel, SaaS, standard DTC.
- Under $30k/mo per brand. Not enough volume to negotiate dedicated pricing anyway.
- Developer-led products where API quality matters more than basis points.
- Testing a new brand before committing to full underwriting.
When it isn't
- High-risk categories where termination risk is structural.
- Multi-brand operators above $100k/mo portfolio volume.
- Subscription businesses where your CLTV depends on account stability over 24-36 months.
- Businesses that need per-brand descriptors and individual underwriting.
What operators need to know
- Stripe is an aggregator. So is Square. So is PayPal. So is Adyen's sub-merchant product. The model is dominant because it's fast and predictable — until it isn't.
- Moving off an aggregator takes 30-60 days. Underwriting, integration, tokenization migration, subscription re-billing. Plan the move before you need it.
- Multi-brand operators usually end up hybrid. Stripe or Square for low-risk brands, dedicated acquirer for high-risk brands, orchestration layer on top. That's the architecture multiflow is designed for.
See PayFac, payment processor, and merchant account.