Securities and Exchange Commission (SEC) said listed companies should have at least 10 percent free float to increase market liquidity.
"We are looking to increase liquidity seriously for a minimum 10 percent float," SEC Chairman Thilak Karunaratne has told Reuters in an interview.
"Final decision will be taken as soon as possible, hopefully before June," he has added.
The 10 percent free float rule will require the companies to have at least 10 percent of the shares to be independent of the company and its management and available for public trading when they get listed.
The SEC Chairman has said that there was a risk a minimum float requirement could be counter-productive as some big firms may decide to delist, and he would consult with the market before finalizing the regulation.
"We don't want anybody to get delisted. Perhaps we will talk to big companies and multi-nationals and ask their view on the minimum float," he has said.