Some 6,000 U.S. public companies are preparing to file their first financial statements using the XBRL tagging system. But with many companies using an abundance of unique tags known as extensions, regulators are concerned it could defeat the purpose of the interactive data system.

XBRL stands for Extensible Business Reporting Language, the new method mandated by the Securities and Exchange Commission for public companies to file their financial statements. So far, a little more than 1,500, or about 30 percent, of all public companies have used XBRL when filing their financial reports. The next wave of companies are currently preparing to make their first submissions under the new system this summer as the SEC’s phased-in reporting requirement takes effect.