"We are proud of the role that the Federal Reserve Banks have played in driving the payments industry toward an improvement of this magnitude. This rule expands upon the work we have done to effectively test the market's readiness for same day ACH with our opt-in service," said Marie Gooding, first vice president and retail payments product director of the Federal Reserve Bank of Atlanta. "After years of promoting the benefits of expedited processing and settlement of ACH transactions, the Federal Reserve Banks are gratified in the knowledge that all ACH Network participants will benefit from NACHA's Same-Day ACH rule."

The rule will be implemented in three phases, with the first of these phases effective Sept. 23, 2016. 

Phase I will provide for same-day processing of ACH credit transactions to include hourly payroll, person-to-person payments and same-day bill payments.

Phase 2 will add ACH debits to same-day processing and will allow for consumer bill payments to be included. Phase 3 will require receiving institutions to provide faster ACH credit funds availability.

The Same-Day ACH Rule was approved in May 2015, and will require all receiving depository financial institutions to receive same day transactions and provide faster funds availability to customers.

The rule also provides for a same-day entry fee as a means for receiving institutions to recover costs associated with enabling and supporting mandatory receipt of same-day ACH transactions.

FedACH Services will offer two new same-day settlement windows providing settlement at 1 p.m. and 5 p.m. Eastern time. Additional information surrounding deadlines and processing windows will be made available once the ACH operators have discussed such details in the coming weeks, the Fed said.

Credit union trade associations praised the move but also expressed concern about costs.

"NAFCU and our members appreciate the Federal Reserve's recognition of the industry-wide movement toward the adoption of faster payment technologies," Senior Vice President of Government Affairs and General Counsel Carrie Hunt said. "While NAFCU and our members believe that ubiquitous Same-Day ACH capability represents an improvement for the nation's payment system, we continue to have significant concerns regarding the board's inadequate interbank fee and for credit unions to affordably receive, process and settle these payments in near-real time."

"In comments to NACHA and the Federal Reserve, CUNA expressed concerns with the requirements that all receiving financial institutions have the ability to receive and post same-day ACH payments. While we support the goal of a faster payments system, we believe more could have been done to consider the implementation and other ongoing costs credit unions will face – particularly our smaller credit unions," CUNA Chief Advocacy Offer Ryan Donovan said.