The U.S. Securities and Exchange Commission (SEC) Wednesday approved new rules for the three major U.S. listing markets to toughen standards for companies going public through a reverse merger. Currently, reverse merger companies, like other operating companies, can pay to be listed on an exchange. However, in some cases, regulators and auditors have greater difficulty getting reliable information from reverse merger companies, particularly those based overseas, the SEC said. The SEC launched an initiative last summer to determine whether certain companies with foreign operations -- including those that were the product of reverse mergers -- were accurately reporting their financial results, and to assess the quality of the audits being done by the auditors of these companies. The SEC and U.S. exchanges in recent months have suspended or halted trading in more than 35 companies based overseas, including some companies formed by reverse mergers, as they lacked current and accurate financial information. Meanwhile, in June the SEC issued an investor bulletin warning investors about companies that engage in reverse mergers. To prevent accounting fraud and protect investors, Nasdaq, NYSE, and NYSE Amex proposed additional rules to impose more stringent listing requirements for reverse merger companies. Under the new rules, a reverse merger company applying to list is required to complete an one-year \"seasoning period\" by trading in the U.S. over-the-counter market or on another regulated U.S. or foreign exchange following the reverse merger, and to file all required reports with the SEC, including audited financial information. In addition, the company has to maintain the requisite minimum share price for a sustained period, and for at least 30 of the 60 trading days, immediately prior to its listing application and the exchange\'s decision to list. \"Placing heightened requirements on reverse merger companies before they can become listed on an exchange will provide greater protections for investors,\" SEC Chairman Mary L. Schapiro said. However, reverse merger companies would generally be exempt from these special requirements if they are listing in connection with a substantial firm commitment underwritten public offering, or the reverse merger has submitted at least four annual reports with audited financial statements to the SEC.