Mumbai: Patni Computer Systems Ltd has filed its registration statement (Form F-1) with the US Securities and Exchange Commission (SEC), for its Initial Public Offering of 6,875,000 American Depository Shares (ADSs).

Each ADS represents two equity shares of Rs2 par value. The proposed ADS offering comprises 5.125 million primary ADSs and 1.75 million secondary ADSs and up to an additional 1.03125 million in primary ADSs under the greenshoe option given to the underwriters.

The ''invitation to participate'' in the secondary offering is scheduled to start on November 24, 2005, and close on December 1, 2005.

Updating its 2005 guidance provided in October 2005, Patni has said that though it continues to maintain its 2005 revenue guidance in the range of $448 million - $450 million, it has revised its operating margin guidance downwards from 16.00 per cent to 16.50 per cent earlier to 15.75 per cent to 16.25 per cent.

This downward revision, the company says, has been necessitated primarily due to fluctuations in the foreign exchange rates and an increase in subcontractor expenses.

Accordingly, Patni has updated its net income guidance for 2005 to $63 million - $64 million.