ACH (Automated Clearing House)
ACH (Automated Clearing House) is the US network that moves batched electronic credits and debits, such as payroll, bill payments and business-to-business transfers, between bank and credit union accounts. Payments settle the same day or on a later business day, not in real time.
Jurisdiction: United States: rules set by Nacha; settlement through the Federal Reserve. Volumes are for calendar year 2025 as published by Nacha on 28 January 2026.
How it works
Nacha governs the ACH Network, which reaches all US bank and credit union accounts. In 2025 it carried 35.2 billion payments worth $93 trillion, up nearly 5% in number. Business-to-business volume grew almost 10%, to close to 8.1 billion payments.
The network is open 23 hours and 15 minutes each business day and settles four times a day. Settlement runs through the Federal Reserve's settlement service, which is closed on weekends, federal holidays and from 6:30 p.m. to 7:30 a.m. ET on business days. Same Day ACH went live in 2016 and carried 1.4 billion payments worth $3.9 trillion in 2025. Its $1 million per-payment limit rises tenfold on 17 September 2027.
Because settlement happens only when the Fed's service is open, ACH value does not move on weekends or federal holidays. Nacha notes that paydays falling on a weekend or holiday are paid on the prior business day, while bill payments are collected on the next business day. Treasury teams plan funding around those dates and the settlement windows.
Example
A US firm submits $2,000,000 of customer ACH debits on Thursday for next-day settlement, so the funds settle on Friday. If Friday is a federal holiday, settlement moves to Monday. Payouts promised against those funds over the long weekend then need another source of cover.
Frequently asked questions
What is the difference between ACH and a wire?
A Fedwire transfer settles individually and is final once processed. ACH payments are batched and settle in scheduled windows on business days.
When does the Same Day ACH limit change?
Nacha has announced a tenfold increase in the per-payment limit, from $1 million, effective 17 September 2027.
Where Polynopsis fits
Polynopsis keeps ACH transfers in flight until they settle, so money sent today for settlement tomorrow is not counted as available yet.
Compared with
Related terms
Sources
- What is ACH · Nacha
- Same Day ACH and business-to-business payments propel ACH Network volume growth in 2025 (28 January 2026) · Nacha
- Fedwire Funds Services · Board of Governors of the Federal Reserve System
Know where all your money is.
Polynopsis gives cross-border payment teams one live position across every bank, payout partner, exchange and wallet, including money in flight, and warns before a corridor runs dry.
About Polynopsis
Polynopsis is liquidity management software for cross-border payment companies. The name joins poly, many, and synopsis, a seeing together: one live view of money spread across many banks, payout partners, exchanges and stablecoin wallets, including money in flight, with a warning before any corridor runs dry.
Why it is called Polynopsis · About Polynopsis · Glossary · Corridor runway calculator