It is understood the watchdog is unhappy over the way Marconi handled information about its trading problems, which led to two profits warnings in July and September.
The warnings left Marconi in financial turmoil and shaved billions of pounds off its market value.
Rules for listed companies say they must keep the market informed of any price-sensitive information immediately.
The FSA told VNUNet it ‘cannot discuss anything ongoing’.
However, it said that in the case of any listed company they had taken disciplinary action against, ‘we hope to publish after the action’.
‘It is important with any kind of disciplinary action that a proper legal process is followed,’ said the spokesman.
A Marconi spokesman said: ‘I’m not commenting on a draft report that hasn’t been published and I haven’t seen.’
Marconi faces class action lawsuits from US investors regarding its communication to the market last year.
The FSA said that any report would be published no earlier than next month.
Mark McMullen joins the private client services team from Smith & Williamson
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The firm reports 7.6% global fee income growth for the year ending 31 December 2016