A group of U.S. investment banks is getting together to create another market for trading private placements.

Citi, Lehman Brothers, Merrill Lynch, Morgan Stanley and The Bank of New York Mellon announced the establishment of Open Platform for Unregistered Securities, to be known as OPUS-5, which will provide trade reservation, shareholder tracking and transfer management for privately offered equity securities (known as 144A securities because they are transacted under Rule 144A of the Securities Act of 1933).

The banks say that OPUS-5 will support and enable an open platform with multiple market makers and is designed to provide broad liquidity to the U.S. private placement market and facilitate greater access to capital for issuers in the 144A equities market. The platform will also monitor the number of shareholders in these issues. OPUS-5 is expected to launch in September.

“The participation in OPUS-5 by four of the world’s leading securities firms and The Bank of New York Mellon as independent administrator will promote liquidity and efficiency for qualified institutional buyers who trade 144A equity securities and enhance issuers’ capital raising efforts,” they say, adding that additional firms are expected to participate in OPUS-5 over time.