ACH, short for Automated Clearing House, is the electronic network that US banks and credit unions use to move money between accounts in batches. Payroll direct deposits, mortgage and utility debits, supplier invoices and many advertising platform charges travel over it. It exists because paper cheques were costly to clear and businesses needed a standard way to push or pull funds from almost any US bank account without a card. Nacha, formerly the National Automated Clearing House Association, writes the rules; the Federal Reserve and a private bank-owned operator process the payments.

In 2025 the network carried 35.2 billion payments worth $93 trillion, according to Nacha.

How an ACH payment moves

Five parties are involved. The originator starts the payment, such as an employer running payroll or an ad platform collecting a balance. Its bank is the ODFI (originating depository financial institution). The ACH operator sorts and routes the entries. The RDFI (receiving depository financial institution) is the bank holding the other account, and the receiver is its customer.

The two US operators are FedACH, run by the Federal Reserve Banks, and the Electronic Payments Network (EPN), run by The Clearing House, which is owned by large banks.

A payment can travel in either direction. An ACH credit pushes money: an employer's bank sends salaries out to employees' banks. An ACH debit pulls money: a utility, a gym or an ad platform, holding the account holder's authorisation, instructs its bank to collect a sum from the payer's bank. Debits make ACH useful for recurring billing and account for most of its risk.

Originators submit files built from fixed-width text records of 94 characters each: a file header, one or more batch headers, entry detail records carrying the routing number, account number and amount, optional addenda records with remittance information, then batch and file control records with totals. Each batch carries a Standard Entry Class (SEC) code describing the authorisation behind it. PPD covers consumer payments authorised in advance, such as payroll and bill payments. CCD covers transfers between companies. WEB applies when a consumer authorised a debit online and TEL when the authorisation was given by phone.

Timing depends on the window. Standard next-day entries settle at 8:30 a.m. Eastern Time on the settlement date, according to the Federal Reserve's FedACH processing schedule. Same Day ACH runs three windows, with submission deadlines of 10:30 a.m., 2:45 p.m. and 4:45 p.m. Eastern and settlement at 1:00 p.m., 5:00 p.m. and 6:00 p.m. respectively.

Because no one checks the payer's balance at the moment a debit is created, ACH relies on returns. A receiving bank that cannot post an entry sends it back with a reason code. Debits from business accounts can be returned within two banking days. Consumers who say they never authorised a debit have 60 calendar days to dispute it, according to Increase's ACH returns documentation. Originators whose unauthorised returns exceed 0.5% of debits, or total returns 15%, face scrutiny.

How it differs from card payments

A card payment is authorised in real time. The card network asks the issuing bank whether the funds or credit line exist, and the merchant gets an answer in seconds. The merchant pays interchange to the issuer plus network and processor fees, usually as a percentage of the sale. ACH has no live authorisation step and no percentage interchange. Banks charge per entry, so moving $50 and $50,000 can cost the same.

Stripe prices ACH Direct Debit at 0.8% capped at $5.00 per charge and claims savings of "up to 70%" against cards, according to Stripe's bank debits page. That figure is the company's own claim. Confirmation takes four business days, so a merchant shipping goods against an ACH debit risks it bouncing later.

Disputes differ too. Card chargebacks run through network rules with structured evidence; an unauthorised ACH debit is simply returned. Under the Federal Reserve's Regulation II, debit interchange for large issuers has been capped at 21 cents plus 0.05% since 2011; credit card interchange is uncapped.

Origin and evolution

The ACH grew out of a 1968 committee of California bankers called SCOPE, the Special Committee on Paperless Entries, formed because cheque volumes were outrunning processing capacity, according to Nacha's history. The first ACH association started in California in 1972, others followed, and the regional groups formed Nacha in 1974 to administer national rules and a standard format. The Social Security Administration began testing direct deposit in 1975.

Internet- and phone-initiated payments arrived in 2001.

Same Day ACH was the largest structural change. It launched on September 23, 2016 for credits, with debits added in September 2017. The per-payment limit rose from $25,000 to $100,000 in March 2020 and to $1 million in March 2022, and the operating window was extended by two hours in March 2021. Each step answered businesses that wanted ACH's low cost without the wait.

Why it matters for marketers

For most marketers ACH is invisible plumbing, but it shapes how advertising is paid for and how publishers and creators are paid. Google Ads supports automatic payments from a bank account in the US and several European countries, verified by a small challenge deposit, with bank payments taking up to five business days to process, according to Google's help page. In June 2024 Google told a small group of advertisers that cards would no longer be accepted and that they had to move to bank-based methods or monthly invoicing by July 31, 2024.

Card billing gives advertisers float and rewards; bank debits give platforms cheaper collection. The tension surfaced in April 2026, when Amazon began moving some US advertisers off card billing onto deductions from seller proceeds, then delayed the change to August 1, 2026 and offered Pay by Invoice as an alternative.

On the supply side, AdSense and YouTube earnings leave Google by bank transfer. The YouTube payment timeline published in January 2026 puts electronic funds transfers at up to seven business days, against up to 15 for wire transfers. Google's end of euro cheque payouts on August 7, 2026 shows the slow retreat of paper, after it added PayPal Hyperwallet for US publishers in 2025.

Limitations and disputes

Speed remains the main criticism. Same Day ACH settles in scheduled windows, nothing moves at weekends, and the 60-day consumer return window means a merchant can lose money weeks after being paid.

Fraud has shifted rather than disappeared. The Association for Financial Professionals (AFP) found that 79% of organisations faced actual or attempted payments fraud in 2024 and 63% experienced business email compromise, the scheme in which a criminal impersonates a supplier and asks for payments to be redirected, often by ACH credit. Cheques were still the most attacked method, cited by 63% of organisations, according to Nacha's summary of the AFP survey. "AFP is not exaggerating when it calls checks 'the least secure' payment method," said Michael Herd, Nacha's executive vice president for ACH network administration. Nacha administers the rail it recommends.

Processor savings claims compare list prices, not the cost of returns, verification and slower fulfilment. Regulation II is itself contested: in August 2025 a federal court in North Dakota ruled that the Fed exceeded its authority and vacated the rule, staying that decision pending appeal, while a Kentucky court upheld it a month later, according to R Street.

Not the same as

  • Wire transfer: Fedwire moves individual payments in real time with immediate, final settlement. Wires cost more and suit large one-off transfers; ACH suits volume.
  • RTP and FedNow: instant payment networks launched by The Clearing House in 2017 and the Federal Reserve on July 20, 2023. They settle each payment in seconds, around the clock, but only push credits; ACH also handles debits.
  • EFT: electronic funds transfer is an umbrella term covering ACH, wires and card transactions. Google's AdSense uses "EFT" for its bank payouts.
  • Foreign clearing houses: "ACH" is also a generic name for batch bank networks elsewhere, such as Bacs in the UK and SEPA Direct Debit in the euro area. Those have their own rules; Nacha's apply only to the US network.

Recent developments

ACH volume grew almost 5% in 2025, with Same Day ACH up 16.7% to 1.4 billion payments worth $3.9 trillion and business-to-business payments up almost 10% to close to 8.1 billion, according to Nacha's January 29, 2026 release. "Both of those statistics point to businesses large and small turning their backs on checks," said Jane Larimer, Nacha's president and chief executive.

Rule changes in 2026 targeted fraud. From March 20, 2026, all ODFIs and the largest originators and processors had to run risk-based monitoring for payments authorised under false pretences, extended to everyone else on June 22, 2026, according to Nacha's rules page. The same March date required the descriptions "PAYROLL" and "PURCHASE" on payroll credits and online purchase debits, and from September 18, 2026 standard ACH credits had to be available by 9:00 a.m. local time on settlement day, according to Regions Bank.

On April 27, 2026, Nacha announced that the Same Day ACH limit will rise to $10 million per payment on September 17, 2027.

Agentic commerce has so far been built on cards. OpenAI's Instant Checkout uses stored cards and scoped tokens, the Universal Commerce Protocol passes credentials through tokenised payment handlers, and Visa's agent infrastructure binds tokens to cards and devices. A Google Pay API update in April 2026 added recurring card transactions, long a job for ACH debits. HUMAN Security found agent behaviour hard to separate from automated fraud, a problem a rail with a 60-day return window would feel sharply.

Timeline

  • 1968 - California bankers form SCOPE to plan paperless payments.
  • 1972 - The first ACH association begins operating in California.
  • 1974 - Regional ACH associations form Nacha to administer national rules.
  • 1975 - The Social Security Administration begins testing direct deposit.
  • 2001 - Internet- and phone-initiated ACH payments become available.
  • October 1, 2011 - Regulation II caps debit card interchange for large issuers at 21 cents plus 0.05%.
  • September 23, 2016 - Same Day ACH launches for credit payments.
  • 2017 - The Clearing House launches the RTP instant payment network.
  • September 2017 - Same Day ACH adds debits.
  • March 2020 - Same Day ACH limit rises from $25,000 to $100,000.
  • March 2021 - Same Day ACH window extended by two hours.
  • March 2022 - Same Day ACH limit rises to $1 million.
  • July 20, 2023 - The Federal Reserve launches FedNow.
  • June 2024 - Google Ads moves some advertisers from cards to bank-based payment or invoicing.
  • August 2025 - A North Dakota federal court vacates Regulation II, staying the ruling pending appeal.
  • January 29, 2026 - Nacha reports 35.2 billion ACH payments worth $93 trillion for 2025.
  • March 20, 2026 - Fraud monitoring phase one and standard PAYROLL and PURCHASE descriptions take effect.
  • April 27, 2026 - Nacha announces a $10 million Same Day ACH limit.
  • June 22, 2026 - Fraud monitoring extends to all remaining originators and processors.
  • August 1, 2026 - Amazon's delayed advertiser payment change takes effect.
  • September 18, 2026 - Standard ACH credits must be available by 9:00 a.m. local time on settlement day.
  • September 17, 2027 - The $10 million Same Day ACH limit is scheduled to take effect.

Summary

Who: Nacha writes the rules. The Federal Reserve (FedACH) and The Clearing House (EPN) operate the network. Banks, employers, billers, advertising platforms and processors such as Stripe originate and receive payments.

What: A batch network for US bank-to-bank credits and debits, using fixed-width files, SEC codes for authorisation types and a return system in place of live authorisation.

When: Planned from 1968, first operated in California in 1972 and governed by Nacha since 1974. Same Day ACH arrived in 2016, and the per-payment limit is due to reach $10 million on September 17, 2027.

Where: In the United States, between accounts at banks and credit unions. Comparable networks elsewhere, such as Bacs and SEPA, run under separate rules.

Why: Cheques were costly and slow. ACH moves high volumes cheaply and supports recurring debits, at the cost of slower settlement, delayed failure and return risk that card payments handle differently.