Key takeaways
- ACH moves money between US bank accounts in batches and usually costs far less than card payments for large invoices.
- Same Day ACH speeds settlement, while standard ACH typically settles within one to two business days.
- Returns, such as insufficient funds or unauthorized debits, must be handled within strict timeframes.
- Nacha fraud monitoring rules phase in during 2026, starting March 20 for the largest originators and June 22 for others.
For business-to-business payments, cards can be expensive on large invoices, and checks are slow and error-prone. ACH, the US network for electronic bank transfers, sits in between: low cost, reliable and well suited to recurring and high-value payments.
How ACH works
- The payer authorizes a debit from their bank account, or initiates a credit to yours.
- Your bank or payment provider, the originating depository financial institution (ODFI), submits the entry to the ACH network.
- The receiver’s bank, the RDFI, posts the transaction to the account.
- Funds settle according to the ACH schedule; returns can follow if something is wrong.
ACH versus cards for B2B
| ACH | Cards | |
|---|---|---|
| Typical cost | Low, often a flat fee per transaction | Percentage-based, higher on large amounts |
| Speed | Same day to a few business days | Authorization immediate; settlement within days |
| Best for | Large invoices, recurring B2B billing, payroll | Small payments, consumers, immediate confirmation |
| Failure handling | Returns arrive after submission | Declines happen at authorization |
Returns you need to handle
ACH entries can be returned after submission, for example for insufficient funds, closed accounts, invalid account numbers or unauthorized debits. Return reason codes and time limits are defined in the Nacha Operating Rules. Your systems should record returns against invoices, notify the right people and trigger follow-up automatically.
Preventing fraud and errors
- Validate bank account details before the first debit, which Nacha rules require for certain online (WEB) debits.
- Capture clear, retained authorizations with the payer’s agreement to the terms.
- Watch for changes to supplier bank details, a common target for business email compromise; verify changes through a known contact.
- Use your bank’s or provider’s fraud tools and positive-pay style controls where available.
Nacha fraud monitoring rules in 2026
Nacha approved new rules requiring risk-based fraud monitoring across more participants in the ACH network. They phase in during 2026:
| Phase | Effective date | Who it covers |
|---|---|---|
| Phase 1 | March 20, 2026 | Larger participants, including non-consumer originators, third-party service providers and senders with 6 million or more ACH originations in 2023, plus ODFIs and larger RDFIs |
| Phase 2 | June 22, 2026 | All remaining non-consumer originators, third-party service providers and third-party senders, and RDFI credit monitoring |
The rules require processes and procedures reasonably intended to identify ACH entries initiated due to fraud, including false pretenses such as business email compromise. Confirm with your bank how the rules apply to your business and what evidence of monitoring they expect.
Automating ACH in your CRM
- Send payment requests with a secure link for bank details or account verification.
- Store tokens or references from your payment provider, not raw account numbers, wherever possible.
- Track status from pending to settled or returned on each payment record.
- Alert account owners on returns and retry or escalate according to policy.
We integrate payment platforms with Salesforce, including bank-based payments; see our payment solutions.
Frequently asked questions
How long does an ACH payment take?
Same Day ACH can settle on the same business day; standard ACH typically settles within one to two business days.
Is ACH cheaper than card payments?
For larger amounts, usually yes, because ACH fees are often flat while card fees are a percentage of the transaction.
Do the 2026 Nacha rules apply to small businesses?
Phase 2 extends fraud monitoring to remaining non-consumer originators from June 22, 2026. Check with your bank about your specific obligations.
