Industry sources say the lights have been burning late at design software vendor Bentley Systems Inc. in preparation for the company going public.

According to sources, the Exton, Pa.-based company is preparing a registration statement for the Securities and Exchange Commission for an initial public offering of its stock. Bentley officials could not be reached for comment. Whether the offering would be successful and how much money would be raised is unknown, but the process would make public much information about the privately held company. Registration statements have to comply with full disclosure requirements of the SEC.

Filings must include a description of the business, biographical material on the officers and directors, the amount of shares of each insider owning more than 10% of the company's securities and a complete financial statement.

In addition to revealing debt and equity status, the statement also must say how the company plans to use the proceeds of the offering.

According to Hoovers Online, a financial information website, Bentley had sales of $190 million and 1,050 employees in 2000. By contrast, publicly traded rival Autodesk, San Rafael, Calif., had year 2001 sales of $947.5 million and 3,584 employees.