Move from a system built for large, systemically important payments to the workhorse rails that carry the enormous volume of ordinary recurring and bulk payments (salaries, subsidies, loan EMIs, utility bills, mutual-fund SIPs) cheaply, precisely because they do not settle gross, transaction by transaction. In the US, the Automated Clearing House (ACH) network (governed by Nacha's operating rules and operated by the Federal Reserve's FedACH and by The Clearing House's EPN) collects individual payment instructions into batch files, submitted by originating banks, and settles the net obligations between banks only at scheduled processing windows, not instantly. Per the Federal Reserve Financial Services' own published Same Day ACH schedule (frbservices.org, as of 2026-07, check current, since these windows too are periodically revised by Nacha rule changes), same-day-eligible entries submitted in one of three windows settle at a fixed time later that same business day: entries submitted between 3:00 a.m. and 10:30 a.m. ET settle at 1:00 p.m. ET; entries submitted between 10:30 a.m. and 2:45 p.m. ET settle at 5:00 p.m. ET; entries submitted between 2:45 p.m. and 4:45 p.m. ET settle at 6:00 p.m. ET; anything submitted after the final window's cutoff waits for the next business day's ordinary (non-same-day) processing.
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Is an ACH payment final once it posts?
Whose balance sheet moves, and when? The originating bank's ledger typically posts the debit or credit to its own customer immediately or same-day for the customer's convenience, but the interbank leg (the actual movement of reserves between the originating and receiving banks) happens only when the batch settles at one of those fixed windows. An ACH credit or debit is provisional, not final, even after it posts to your account: Nacha's operating rules give banks and customers a window to return an entry (for reasons ranging from insufficient funds to an unauthorized debit) after which the entry is unwound. This is the structural opposite of Fedwire: Fedwire trades a fixed, wide daily operating window for irrevocable, instant, transaction-by-transaction finality; ACH trades that instant finality for provisional settlement that becomes final only after its return window closes, in exchange for handling enormous transaction volumes far more cheaply than gross settlement ever could.
What is NACH in India?
India's mandate-based equivalent is NACH (National Automated Clearing House), built and operated by NPCI specifically to consolidate the fragmented, regional Electronic Clearing Service (ECS) systems that preceded it into one national platform with a single set of operating rules. NACH runs on a mandate: a payer authorizes a payee (a lender, a mutual fund, a utility) to debit their account repeatedly, registered once (on paper, via Aadhaar-based e-sign, or via an API-based e-mandate) through NPCI's Mandate Management System. Two flows ride on the same rails: NACH Debit (a mandate-authorized recurring collection (a loan EMI, a SIP, an insurance premium) and NACH Credit (a bulk disbursement) salaries, dividends, government subsidies, one file crediting thousands of accounts at once). Like US ACH, NACH is file-based and batch-processed, run in scheduled cycles across a business day (check the current cycle count and timing at npci.org.in, this, again, is an operational specific set by NPCI circular, not a law of nature), and its debits are provisional until the batch actually settles, which is precisely why a NACH debit can bounce (be dishonoured for insufficient funds) even after it has been presented, generating a return and, typically, a bank-levied dishonour fee (Worked Example 4 computes this cost across a real-sized mandate batch).