The number of firms vying to build a faster U.S. payment system has been whittled down slightly.

The Federal Reserve said Tuesday that 19 private-sector proposals are now under review by nearly 500 members of two separate task forces, one of which was established to chart a path toward a faster payment system, and the other focused on payment system security.

The Fed received more than 20 proposals prior to its April 30 submission deadline, but some of the submissions were withdrawn after an initial evaluation process by McKinsey & Co., the global consulting firm.

The remaining proposals will be assessed against a detailed set of 36 criteria that were established by the two task forces.

The criteria state that private-sector proposals will be deemed effective if they can achieve initial implementation by 2019 and reach all U.S. banks and credit unions by 2021. Likewise, proposals will be judged effective if they allow payment recipients to access their funds within 30 minutes.

In addition, the criteria state that a modernized payment system should be available to users 24 hours a day and 365 days a year. The system should allow the sender to initiate payments based on minimal information, such as the recipient's name, email address or phone number. And it should be available through mobile devices.

The criteria also state that the two parties to the transaction should not be required to know each other's bank account numbers or other sensitive information.

The Fed said Tuesday that the task force work on faster payments will result in a two-part report. The first section is scheduled to be released in January. The second section, which will include an assessment of the private-sector proposals, is targeted for release in mid-2017, according to the Fed.

"In addition to the proposals and the assessments, this section will identify strategic issues deemed important to the successful development of faster payments in the United States and recommend industry actions required to advance their implementation and adoption," the Fed said in a press release.

The Fed-convened task forces do not plan to crown a single winner at the end of the evaluation process. Still, proposals that win praise are expected to gain a leg up in the marketplace.

The Fed has not identified the 19 submitters. But back in May, three firms told American Banker that they had made initial proposals.

Those submitters were Dwolla, which offers real-time payments with BBVA Compass; Ripple Labs, which uses distributed-ledger technology to transfer value; and The Clearing House, which is owned by the nation's largest banks. The Clearing House said that it submitted a joint proposal with the banking technology vendor FIS.