Brokerages plan trading platform

Citigroup Inc. and three of the largest U.S. brokerage firms plan to create a trading system for unregistered securities as more companies seek to avoid regulation by raising money privately.

Lehman Bros. Holdings Inc., Merrill Lynch & Co., Morgan Stanley and Citigroup expect to begin operating the Open Platform for Unregistered Securities, or OPUS-5, in September, the companies said in a statement Tuesday. OPUS-5 will allow trades, track the number of shareholders and execute transfers in securities sold. The Bank of New York Mellon will administer the system.

Goldman Sachs Group Inc., JPMorgan Chase & Co., Bear Stearns Cos. and FBR Capital Markets Corp. each have recently started markets for trading privately issued securities.

To avoid rules that apply to publicly traded companies, the securities can be sold to no more than 499 buyers, each with at least $100 million in discretionary assets.

In May, Los Angeles-based Oaktree Capital Management raised about $800 million on Goldman Sach’s trading platform.