The reform plan was carried out in November to boost the country's stock market over the long term. It means some shares from existing shareholders can be transferred to raise the proportion of tradable shares in a company.

Among problems was that involving Jiangsu Aosaikang Pharmaceutical Co Ltd. It announced plans on Jan 9 to issue 55.466 million shares for sale at 72.99 yuan ($12.07) each, with as many as 78.6 percent of the shares to be transferred from existing shareholders. The IPO was halted the next day.

The commission carried out new measures on Friday that stated the number of shares sold by existing shareholders should be fewer than the number offered to investors who will hold them for at least 12 months.

The measure was designed to prevent existing shareholders from transferring too many shares and to protect the interests of new shareholders.

An industry expert said the intention behind the measure is good, but it may cause new problems involving interest exchanges between new and existing shareholders.

Another step taken last Friday was intended to further meet the requirement of small and medium-sized investors.

Private Chinese offering funds can open security accounts and invest in the A-share market, according to a statement released by China Securities Depository and Clearing Co Ltd on Tuesday night.

Previously, private offering funds could only have security accounts under the names of their companies or trust products.

The statement also said private offering fund managers cannot apply to open accounts for funds that specialize in subscribing to new shares or investing in stocks under special treatment.

Hong said the move could increase the amount of funds flowing into the secondary market.

China's CSI300 index in biggest loss in 7 months	IPO changes 'will help small investors'