The Financial Industry Regulatory Authority likely will test the market impact of delaying the disclosure of huge corporate bond trades after some of the biggest investors argued that such a move would improve liquidity.

FINRA last week proposed running a pilot program that would give traders 48 hours before having to reveal their so-called block trades to other investors. The effort would allow the industry-funded brokerage regulator, which is overseen by the U.S. Securities and Exchange Commission, to evaluate how delayed transparency might affect corporate bond trading.

Current rules require that block trades be reported within 15 minutes. Brokers and investment firms such as BlackRock Inc. and Pacific Investment Management Co. have long said that such rapid disclosure can make it difficult to execute such trades in less-liquid bonds because the transparency tips off other market participants.

Brokerages have said "there is some amount of trading that is not being done today because the dissemination affects the ability of the broker who's committing capital to recoup a fair return," FINRA Chief Economist Jonathan Sokobin said in an interview on Monday. "But, that's an open question — that's the story that's being told."

Sokobin said that generally there's evidence that disseminating more data is beneficial to markets. FINRA's pilot would test specifically if that's true when data is kept private for 48-hours on trades of more than $10 million in investment-grade debt and trades greater than $5 million for speculative-grade bonds.

The idea for the pilot was backed by a group of industry executives that advises the SEC. The Securities Industry and Financial Markets Association, Wall Street's biggest trade group, has expressed support for the proposed test as did JPMorgan Chase & Co. and Eaton Vance, according to FINRA. At the same time, the regulator said that two market makers for exchange traded funds have expressed concern that the changes would reduce price transparency.